Most of Asimov's popularized science books explain scientific concepts in a historical way, going back as far as possible to a time when the science in question was at its simplest stage. He often gives nationalities, birth dates and death dates for the scientists he mentions, as well as etymologies and pronunciation guides for technical terms. Examples of this style include his Guide to Science, the three-volume set Understanding Physics, and Asimov's Chronology of Science and Discovery.

Asimov was a long-time member of Mensa, albeit reluctantly; he described them as "intellectually combative". He took more joy in being president of the American Humanist Association. The asteroid 5020 Asimov, the magazine Asimov's Science Fiction and two different Isaac Asimov Awards are all named in his honor.

Biography
Asimov was born around January 2, 1920 (his date of birth for official purposes—the precise date is not certain) in Petrovichi shtetl of Smolensk Oblast, RSFSR (now Russia) to Anna Rachel Berman Asimov and Judah Asimov, a Jewish family of millers. They emigrated to the United States when he was three years old; since the parents always spoke Yiddish and English with their son, he never learned Russian. Growing up in Brooklyn, New York, he taught himself to read at the age of five, and remained fluent in Yiddish as well as English. His parents owned a small general store and everyone in the family was expected to work in it. He saw science fiction magazines in the store and began reading them. Around the age of eleven, he began to write his own stories and few years later he was selling them to pulp magazines.

He graduated from Columbia University in 1939 and earned a Ph.D. in chemistry there in 1948. In between, he spent three years during World War II working at the Philadelphia Navy Yard's Naval Air Experimental Station. After the war ended, he was drafted into the U.S. Army, serving for just under nine months before receiving an honorable discharge. In the course of his brief military career, he rose to Corporal on the basis of his typing skills and narrowly avoided participating in the 1946 atomic bomb tests at Bikini Atoll.

After completing his doctorate, he joined the faculty of Boston University, with which he remained associated thereafter. From 1958 this was in a non-teaching capacity, as he became a full-time writer (his writing income already exceeded his academic salary). Being tenured meant that he retained the title of associate professor, and in 1979 the university honored his writing by promoting him to full professor. His personal papers from 1965 onward are archived at their Mugar Memorial Library, where they fill 464 boxes on 71 metres of shelf space.

In 1985, he became President of the American Humanist Association and remained in that position until his death in 1992; his successor was his friend and fellow writer Kurt Vonnegut, Jr. He was a close friend of Star Trek creator Gene Roddenberry.

He married Gertrude Blugerman (1917–1990) on July 26, 1942, and they had two children, David (b. 1951) and Robyn Joan (b. 1955). After an extended separation, they were divorced in 1973, and Asimov married Janet O. Jeppson later that year. Gertrude, born in Canada, died in Boston in 1990.

Asimov was a claustrophile; that is, he enjoyed small, enclosed spaces. In his first volume of autobiography, he recalls a childhood desire to own a magazine stand in a New York City Subway station, within which he imagined he could enclose himself and listen to the rumble of passing trains.

Asimov was afraid of flying, only doing so twice in his entire life (once in the course of his work at the Naval Air Experimental Station and once returning home from the army base in Oahu in 1946). He seldom traveled great distances, partly because his aversion to aircraft made the logistics of long-distance travel complicated; this phobia influenced several of his fiction works, such as the Wendell Urth mystery stories and the Robot novels featuring Elijah Baley. In his later years, he found he enjoyed traveling on cruise ships, and on several occasions he became part of the cruises' "entertainment," giving science-themed talks on ships like the RMS Queen Elizabeth 2.

His physical dexterity was very poor. He never learned how to swim or ride a bicycle, although he did learn to drive a car and found he enjoyed it. He did not learn to operate a car until after he moved to Boston, Massachusetts; in his jokebook Asimov Laughs Again, he describes Boston driving as "anarchy on wheels".

Asimov's wide interests included his participation in his later years in organizations devoted to the operettas of Gilbert and Sullivan and the Nero Wolfe mysteries of Rex Stout. He was a prominent member of the Baker Street Irregulars, the leading Sherlock Holmes society.

Asimov died on April 6, 1992. He was survived by his second wife, Janet, and his children from his first marriage. Ten years after his death, Janet Asimov's edition of Asimov's autobiography, It's Been a Good Life, revealed that his death was caused by AIDS; he had contracted HIV from an infected blood transfusion during heart bypass surgery in 1983. The specific cause of death was heart and renal failure as complications of AIDS.

Janet Asimov writes in the epilogue of It's Been a Good Life that Asimov had wanted to "go public", but his doctors convinced him to remain silent, warning that anti-AIDS prejudice would extend to his family members. Asimov's family considered disclosing his AIDS infection after he died, but the controversy which erupted when Arthur Ashe announced that he had contracted AIDS convinced them otherwise. Ten years later, after Asimov's doctors had died, Janet and Robyn agreed that the AIDS story could be made public.

Intellectual positions
Isaac Asimov was a Humanist and a rationalist. He did not oppose genuine religious conviction in others but vocally opposed superstitious or unfounded beliefs. During his childhood, his father and mother observed the Orthodox Jewish tradition, but did not force this belief upon Asimov, and so he grew up without strong religious influences, coming to believe that the Bible represented Hebrew mythology in the same way that the Iliad recorded Greek mythology. (For a brief while his father, Judah Asimov, worked in the local synagogue to enjoy the familiar surroundings and "shine as a learned scholar" versed in the sacred writings. This experience had little effect upon his son Isaac beyond teaching him the Hebrew alphabet.) For many years, Asimov called himself an atheist, though he felt the term was somewhat inadequate, describing more about what he did not believe than about what he did. Later, he found the term "humanist" a useful substitute.

In his last autobiographical book, Asimov wrote, "If I were not an atheist, I would believe in a God who would choose to save people on the basis of the totality of their lives and not the pattern of their words. I think he would prefer an honest and righteous atheist to a TV preacher whose every word is God, God, God, and whose every deed is foul, foul, foul." The same memoir states his belief that Hell is "the drooling dream of a sadist" crudely affixed to an all-merciful God; if even human governments were willing to curtail cruel and unusual punishments, wondered Asimov, why would punishment in the afterlife not be restricted to a limited term?

Asimov rejected the idea that a human belief or action could merit infinite punishment. If an afterlife of just desserts existed, he claimed, the longest and most severe punishment would be reserved for those who "slandered God by inventing Hell". As his Treasury of Humor and Asimov Laughs Again record, he was amply willing to tell jokes involving the Judeo-Christian God, Satan, the Garden of Eden and other religious topics, expressing the viewpoint that a good joke can do more to provoke thought than hours of philosophical discussion.

Asimov was a progressive on most political issues, and a staunch supporter of the Democratic Party. He was a vocal opponent of the Vietnam War in the 1960s, and in a television interview in the early 1970s he publicly endorsed George McGovern. He was unhappy at what he saw as an irrationalist track taken by many progressive political activists from the late 1960s onwards. In his autobiography In Joy Still Felt, he recalls meeting the counterculture figure Abbie Hoffman; Asimov's impression was that the 1960s' counterculture heroes had ridden an emotional wave which, in the end, left them stranded in a "no-man's land of the spirit" from which he wondered if they would ever return. (This attitude is echoed by a famous passage in Hunter S. Thompson's Fear and Loathing in Las Vegas.)

His defense of civil applications of nuclear power even after the Three Mile Island incident damaged his relations with some of his fellow liberals. In a letter reprinted in Yours, Isaac Asimov, he states that though he would prefer living in "no danger whatsoever" than near a nuclear reactor, he would still prefer a home near a nuclear power plant than in a slum, on Love Canal or near "a Union Carbide plant producing methyl isocyanate" (referring to the Bhopal disaster). He issued many appeals for population control reflecting the perspective articulated by people from Thomas Malthus through Paul R. Ehrlich.

Asimov considered himself a feminist even before Women's Liberation became a widespread movement; he joked that he wished women to be free "because I hate it when they charge". More seriously, he argued that the issue of women's rights was closely connected to that of population control. Furthermore, he believed that homosexuality must be considered a "moral right" on population grounds, as must all consenting adult sexual activity which does not lead to reproduction (Yours, Isaac Asimov).

In the closing years of his life, Asimov blamed the deterioration of the quality of life that he perceived in New York on the shrinking tax base caused by middle class flight to the suburbs. His last non-fiction book, Our Angry Earth (1991, co-written with his long-time friend science fiction author Frederik Pohl), deals with elements of the environmental crisis such as global warming and the destruction of the ozone layer.

Asimov's writing career

Overview

Rowena Morrill depicts Asimov enthroned with symbols of his life's workAsimov's career can be divided into several time periods. His early career, dominated by science fiction, began with short stories in 1939 and novels in 1950. This lasted until about 1958, all but ending after publication of The Naked Sun. He began publishing nonfiction in 1952, co-authoring a college-level textbook called Biochemistry and Human Metabolism. Following the brief orbit of the first man-made satellite Sputnik I by the USSR in 1957, his production of nonfiction, particularly popular science books, greatly increased, with a consequent drop in his science fiction output.

Over the next quarter century, he would write only four science fiction novels. Starting in 1982, the second half of his science fiction career began with the publication of Foundation's Edge. From then until his death, Asimov would publish several sequels and prequels to his existing novels, tying them together in a way he had not originally anticipated.

In his own view, Asimov believed that his most enduring contributions would be his "Three Laws of Robotics" and the Foundation Series (see Yours, Isaac Asimov, p. 329). Furthermore, the Oxford English Dictionary credits his science fiction for introducing the words positronic (an entirely fictional technology), psychohistory (frequently used in a different sense than the imaginary one Asimov employed) and robotics into the English language. Asimov coined the term robotics without suspecting that it might be an original word; at the time, he believed it was simply the natural analogue of mechanics, hydraulics and so forth. (The original word robot derives from the Czech word for "forced labor", robota, and was first employed by the playwright Karel Capek.) Unlike his other two coinages, the word robotics continues in mainstream and technical use with Asimov's original definition. Star Trek: The Next Generation featured androids with "positronic brains", giving Asimov full credit for inventing this (fictional) technology.

Science fiction
Asimov began contributing stories to science fiction magazines in 1939, "Marooned Off Vesta" being his first published story, written when he was 18. Two and a half years later, he published his 32nd short story, "Nightfall" (1941), which has been described as one of "the most famous science-fiction stories of all time". In 1968 the Science Fiction Writers of America voted "Nightfall" the best science fiction short story ever written. In his short anthology Nightfall and Other Stories he wrote, "The writing of 'Nightfall' was a watershed in my professional career ... I was suddenly taken seriously and the world of science fiction became aware that I existed. As the years passed, in fact, it became evident that I had written a 'classic'".

"Nightfall" is an archetypical example of social science fiction, a term coined by Asimov to describe a new trend in the 1940's, led by authors including Asimov and Heinlein, away from gadgets and space opera and toward speculation about the human condition.

The Foundation Series is among Asimov's most famous fiction works.In 1942 he began his Foundation stories—later collected in the Foundation Trilogy: Foundation (1951), Foundation and Empire (1952), and Second Foundation (1953)—which recount the collapse and rebirth of a vast interstellar empire in a universe of the future. Taken together, they are his most famous work of science fiction, along with the Robot Series. Many years later, he continued the series with Foundation's Edge (1982) and Foundation and Earth (1986) and then went back to before the original trilogy with Prelude to Foundation (1988) and Forward the Foundation (1992). The series features his fictional science of Psychohistory in which the future course of the history of large populations can be predicted.

His robot stories—many of which were collected in I, Robot (1950)—were begun at about the same time. They promulgated a set of rules of ethics for robots (see Three Laws of Robotics) and intelligent machines that greatly influenced other writers and thinkers in their treatment of the subject. One such short story, "The Bicentennial Man", was made into a movie starring Robin Williams.

The recent film I, Robot, starring Will Smith, was based on the Hardwired script by Jeff Vintar with Asimov's ideas incorporated later after acquiring the rights to the I, Robot title. It is not related to the I, Robot script by Harlan Ellison, who collaborated with Asimov himself to create a version that captured the spirit of the original. Asimov is quoted as saying that Ellison's screenplay would lead to "the first really adult, complex, worthwhile science fiction movie ever made". The screenplay was published in book form in 1994, after hopes of seeing it in film form were becoming slim.

Besides movies, his Foundation and Robot stories have inspired other derivative works of science fiction literature, many by well-known and established authors such as Roger MacBride Allen, Greg Bear, and David Brin. These appear to have been done with the blessing, and often at the request of, Asimov's widow Janet Asimov.

In 1948 he also wrote a spoof science article, "The Endochronic Properties of Resublimated Thiotimoline". At the time, Asimov was preparing for his own doctoral dissertation. Fearing a prejudicial reaction from his Ph.D. evaluation board, he asked his editor that it be released under a pseudonym, yet it appeared under his own name. During his oral examination shortly thereafter, Asimov grew concerned at the scrutiny he received. At the end of the examination, one evaluator turned to him, smiling, and said "Mr. Asimov, tell us something about the thermodynamic properties of the compound thiotimoline". After a twenty-minute wait, he was summoned back into the Examination Room and congratulated as "Dr. Asimov."

He continued writing short stories for science fiction magazines in the 1950s, which he referred to as his golden decade. A number of these are included in his Best of anthology, including "The Last Question" (1956), on the ability of humankind to cope with and reverse entropy. It was his personal favorite and considered by many to be a contender to "Nightfall". Asimov wrote of it in 1973, “Why is it my favorite? For one thing I got the idea all at once and didn't have to fiddle with it; and I wrote it in white-heat and scarcely had to change a word. This sort of things endears any story to any writer.”

“Then, too, it has had the strangest effect on my readers. Frequently someone writes to ask me if I can give them the name of a story, which they think I may have written, and tell them where to find it. They don't remember the title but when they describe the story it is invariably "The Last Question". This has reached the point where I recently received a long-distance phone call from a desperate man who began, ‘Dr. Asimov, there's a story I think you wrote, whose title I can't remember—‘ at which point I interrupted to tell him it was "The Last Question" and when I described the plot it proved to be indeed the story he was after. I left him convinced I could read minds at a distance of a thousand miles.”

In December 1974, the former Beatle Paul McCartney approached Asimov and asked him if he could write the screenplay for a science-fiction movie musical. McCartney had a vague idea for the plot and a small scrap of dialogue; he wished to make a film about a rock band whose members discover they are being impersonated by a group of extraterrestrials. The band and their imposters would likely be played by McCartney's group Wings, then at the height of their career. Intrigued by the idea, although he was not generally a fan of rock music, Asimov quickly produced a "treatment" or brief outline of the story. He adhered to McCartney's overall idea, producing a story he felt to be moving and dramatic. However, he did not make use of McCartney's brief scrap of dialogue, and probably in consequence, McCartney rejected the story. The treatment now exists only in Boston University's archives.

Beginning in 1977, he lent his name to Isaac Asimov's Science Fiction Magazine (now Asimov's Science Fiction) and penned an editorial for each issue. There was also a short-lived Asimov's SF Adventure Magazine and a companion Asimov's Science Fiction Anthology reprint series, published as magazines (in the same manner as stablemates Ellery Queen's Mystery Magazine and Alfred Hitchcock's Mystery Magazine's "anthologies").

Popular science
During the late 1950s and 1960s, Asimov shifted gears somewhat, and substantially decreased his fiction output (he published only four adult novels between 1957's The Naked Sun and 1982's Foundation's Edge, two of which were mysteries). At the same time, he greatly increased his non-fiction production, writing mostly on science topics; the launch of Sputnik in 1957 engendered public concern over a "science gap", which Asimov's publishers were eager to fill with as much material as he could write.

Meanwhile, the monthly Magazine of Fantasy and Science Fiction invited him to continue his regular non-fiction column, begun in the now-folded bimonthly companion magazine Venture Science Fiction, ostensibly dedicated to popular science, but with Asimov having complete editorial freedom. The first of the F&SF columns appeared in November of 1958, and they followed uninterrupted thereafter, with 399 entries, until Asimov's terminal illness took its toll. These columns, periodically collected into books by his principal publisher, Doubleday, helped make Asimov's reputation as a "Great Explainer" of science and were referred to by him as his only pop-science writing in which he never had to assume complete ignorance of the subjects at hand on the part of his readers. The popularity of his first wide-ranging reference work, The Intelligent Man's Guide to Science, also allowed him to give up most of his academic responsibilities and become essentially a full-time freelance writer.

He published Asimov's Guide to the Bible in two volumes—covering the Old Testament in 1967 and the New Testament in 1969—and then combined them into one 1300-page volume in 1981. Replete with maps and tables, the guide goes through the books of the Bible in order, explaining the history of each one and the political influences that affected it, as well as biographical information about the important characters. Asimov also wrote several essays on the social contentions of his day, including "Thinking About Thinking" and "Science: Knock Plastic" (1967).

The great variety of information covered in Asimov's writings once prompted Kurt Vonnegut to ask, "How does it feel to know everything?" Asimov replied that he only knew how it felt to have the reputation of omniscience—"Uneasy". (See In Joy Still Felt, chapter 30.) In the introduction to his story collection Slow Learner, Thomas Pynchon admitted that he relied upon Asimov's science popularizations (and the Oxford English Dictionary) to provide his knowledge of entropy.

It is a mark of the friendship and respect accorded Asimov by Arthur C. Clarke that the so-called "Asimov-Clarke Treaty of Park Avenue", put together as they shared a cab ride along Park Avenue in New York, stated that Asimov was required to insist that Clarke was the best science fiction writer in the world (reserving second best for himself), while Clarke was required to insist that Asimov was the best science writer in the world (reserving second best for himself). Thus the dedication in Clarke's book Report on Planet Three (1972) reads: "In accordance with the terms of the Clarke-Asimov treaty, the second-best science writer dedicates this book to the second-best science-fiction writer."

Other
In addition to his interest in science, Asimov was also greatly interested in history. Starting in the 1960s, he wrote fourteen popular history books, most notably The Greeks: A Great Adventure (1965), The Roman Republic (1966) and The Roman Empire (1967).

Never entirely lacking wit and humor, towards the end of his life Asimov published a series of collections of limericks, mostly written by himself, starting with Lecherous Limericks, which appeared in 1975. Limericks: Too Gross, whose title displays Asimov's love of puns, contains 144 limericks by Asimov and an equal number by John Ciardi. He even created a slim volume of Sherlockian limericks (and embarrassed one fan by autographing her copy with an impromptu limerick that rhymed 'Nancy' with 'romancy').

Asimov's best attempt at Yiddish humor is found in Azazel, The Two Centimeter Demon where the two characters, both Jewish, talk over dinner, or lunch, or breakfast, the anecdotes of "George" and his friend Azazel. Asimov's Treasury of Humor is both a working joke book and a treatise propounding his views on humor theory. According to Asimov, the most essential element of humor is an abrupt change in point of view, one that suddenly shifts focus from the important to the trivial, or from the sublime to the ridiculous.

Particularly in his later years, Asimov to some extent cultivated an image of himself as an amiable lecher. In 1971, as a response to the popularity of sexual guidebooks such as The Sensuous Woman (by "J") and The Sensuous Man (by "M"), Asimov published The Sensuous Dirty Old Man under the byline "Dr. 'A'", but with his full name prominently displayed on the cover.

Asimov published two volumes of autobiography, taking their titles from Wordsworth: In Memory Yet Green (1979) and In Joy Still Felt (1980). A third autobiography, I. Asimov: A Memoir, was published in April 1994. The epilogue was written by his widow Janet Asimov shortly after his death. It's Been a Good Life (2002), edited by Janet, is a condensed version of his three autobiographies.

Literary themes
Much of Asimov's fiction dealt with themes of paternalism. His first robot story, "Robbie", concerned a robotic nanny. Just as well, Lenny deals with the capacity of robopsychologist Susan Calvin to feel maternal love towards a robot whose positronic brain capacities are those of a 3-year-old. As the robots grew more sophisticated, their interventions became more wide-reaching and subtle. In "Evidence", a robot masquerading as a human successfully runs for elective office. In "The Evitable Conflict", the robots run humanity from behind the scenes, acting as nannies to the whole species.

Later, in Robots and Empire, a robot develops what he calls the Zeroth Law of Robotics, which states that "A robot may not injure humanity, nor, through inaction, allow humanity to come to harm". He also decides that robotic presence is stifling humanity's freedom, and that the best course of action is for the robots to phase themselves out. A non-robot novel, The End of Eternity, features a similar conflict and resolution. The significance of the Zeroth Law is that it outweighs and supersedes all other Laws of Robotics: if a robot finds himself in a situation whereby he must murder one or more humans (a direct violation of the First Law of Robotics) in order to protect all of humanity (and preserve the Zeroth Law), then the robot's positronic programming will require him to commit murder for humanity's sake.

In The Foundation Series (which did not originally have robots), a scientist implements a semi-secret plan to create a perfect society over the course of 1000 years. This series has its version of Platonic guardians, called the Second Foundation, to perfect and protect the plan. When Asimov stopped writing the series in the 1950s, the Second Foundation was depicted as benign protectors of humanity. When he revisited the series in the 1980s, he made the paternalistic themes even more explicit.

Foundation's Edge introduced the planet Gaia, obviously based on the Gaia hypothesis. Every animal, plant, and mineral on Gaia participated in a shared consciousness, forming a single super-mind working together for the greater good. In Foundation and Earth, the protagonist must decide whether or not to allow the development of Galaxia, a larger version of Gaia, encompassing the entire galaxy. Gaia is one of Asimov's best attempts at exploring the possibility of a collective awareness, and is compounded further in Nemesis, in which the planet Erythro composed primarily of prokaryotic life has a mind of its own and seeks communion with human beings.

Foundation and Earth introduces robots to the Foundation universe. Two of Asimov's last novels, Prelude to Foundation and Forward the Foundation, explore their behavior in fuller detail. The robots are depicted as covert operatives, acting for the benefit of humanity.

Another frequent theme, perhaps the reverse of paternalism, is social oppression. The Currents of Space takes place on a planet where a unique plant fiber is grown; the agricultural workers there are exploited by the aristocrats of a nearby planet. In The Stars, Like Dust, the hero helps a planet that is oppressed by an arrogant interplanetary empire, the Tyranni.

Often the victims of oppression are either Earth people (as opposed to colonists on other planets) or robots. In "The Bicentennial Man", a robot fights prejudice to be accepted as a human. In The Caves of Steel, the people of Earth resent the wealthier "Spacers" and in turn treat robots (associated with the Spacers) in ways reminiscent of how whites treated blacks, such as addressing robots as "boy". Pebble in the Sky shows an analogous situation: the Galactic Empire rules Earth and its people use such terms as "Earthie-squaw", but Earth is a theocratic dictatorship that enforces euthanasia of anyone older than sixty.

One hero is Bel Arvardan, an upper-class Galactic archeologist who must overcome his prejudices. The other is Joseph Schwartz, a 62-year-old twentieth-century American who had emigrated from Europe, where his people were persecuted (he is quite possibly Jewish), and is accidentally transported forward in time to Arvardan's period. He must decide whether to help a downtrodden society that thinks he should be dead.

Yet another frequent theme in Asimov is rational thought. He invented the science-fiction mystery with the novel The Caves of Steel and the stories in Asimov's Mysteries, usually playing fair with the reader by introducing early in the story any science or technology involved in the solution. Later, he produced non-SF mysteries, including the novel Murder at the ABA (1976) and the "Black Widowers" short stories, in which he followed the same rule. In his fiction, important scenes are often essentially debates, with the more rational, humane—or persuasive—side winning.

Criticisms
One of the most common impressions of Asimov's fiction work is that his writing style is extremely unornamental. In 1980, SF scholar James Gunn wrote of I, Robot that:

“Except for two stories—"Liar!" and "Evidence"—they are not stories in which character plays a significant part. Virtually all plot develops in conversation with little if any action. Nor is there a great deal of local color or description of any kind. The dialogue is, at best, functional and the style is, at best, transparent. [...] The robot stories—and, as a matter of fact, almost all Asimov fiction—play themselves on a relatively bare stage.

This description applies well to a large proportion of Asimov's fiction, including that written after 1980. Gunn observes that there are places where Asimov's style rises to the demands of the situation; he cites the climax of "Liar!" as an example. Sharply-drawn characters occur at key junctures of his storylines: in addition to Susan Calvin in "Liar!" and "Evidence", we find Arkady Darell in Second Foundation, Elijah Baley in The Caves of Steel and Hari Seldon in the Foundation prequels. (In Forward the Foundation, Seldon becomes a partial mirror of Asimov himself.)”

These criticisms are to some extent the flip side of Asimov's aforementioned rationalism: his books, like his characters, tend to be cerebral and more interested in ideas and puzzles than in character and feeling. His idea of "psychohistory," where the individual quirks of human beings could be averaged out at the statistical level of an entire galaxy's population, is perhaps revealing in that regard. What helps keep Asimov's fiction readable is the charm of the author, which is conveyed to his characters.

Asimov was also criticised for the lack of sex and aliens in his science fiction. Asimov once explained that his reluctance to write about aliens came from an incident early in his career when Astounding's editor John Campbell rejected one of his early science fiction stories because the alien characters were portrayed as superior to the humans. He decided that, rather than write weak alien characters, he would not write about aliens at all. Nevertheless, in response to these criticisms he wrote The Gods Themselves, which contains aliens, sex, and alien sex. Asimov said that of all his writings, he was most proud of the middle section of The Gods Themselves.

Others have criticised him for a lack of strong female characters in his early work. In his autobiographical writings, he acknowledges this, and responds by pointing to inexperience. His later novels, written with more female characters but in essentially the same prose style as his early SF stories, brought this matter to a wider audience. For example, the 25 August 1985 Washington Post's "Book World" section reports of Robots and Empire as follows:

In 1940, Asimov's humans were stripped-down masculine portraits of Americans from 1940, and they still are. His robots were tin cans with speedlines like an old Studebaker, and still are; the Robot tales depended on an increasingly unworkable distinction between movable and unmovable artificial intelligences, and still do. In the Asimov universe, because it was conceived a long time ago, and because its author abhors confusion, there are no computers whose impact is worth noting, no social complexities, no genetic engineering, aliens, arcologies, multiverses, clones, sin or sex; his heroes (in this case R. Daneel Olivaw, whom we first met as the robot protagonist of The Caves of Steel and its sequels) feel no pressure of information, raw or cooked, as the simplest of us do today; they suffer no deformation from the winds of the Asimov future, because it is so deeply and strikingly orderly.

A considerable portion of such criticism boils down to the charge that Asimov's works are simply dated. In fact, some details of Asimov's imaginary future technology as he described more than fifty years ago have not aged well. He has, for example, described powerful robots and computers from the distant future as still using punch cards or punch tape and engineers using slide rules. His stories also have occasional internal contradictions: names and dates given in The Foundation Series do not always agree with one another, for example. Some such errors may plausibly be due to mistakes the characters make, since characters in Asimov stories are seldom fully informed about their own situations. Other contradictions resulted from the many years elapsed between the time Asimov began the Foundation series and when he resumed work on it; occasionally, advances in scientific knowledge forced him to retcon his own fictional history.

Other than the books by Gunn and Patrouch, there is a relative dearth of "literary" criticism on Asimov (particularly when compared to the sheer volume of his output). Cowart and Wymer's Dictionary of Literary Biography (1981) gives a possible reason:

His words do not easily lend themselves to traditional literary criticism because he has the habit of centering his fiction on plot and clearly stating to his reader, in rather direct terms, what is happening in his stories and why it is happening. In fact, most of the dialogue in an Asimov story, and particularly in the [Foundation] trilogy, is devoted to such exposition. Stories that clearly state what they mean in unambiguous language are the most difficult for a scholar to deal with because there is little to be interpreted.

In fairness, Gunn and Patrouch's respective studies of Asimov both take the stand that a clear, direct prose style is still a style. Gunn's 1982 book goes into considerable depth commenting upon each of Asimov's novels published to that date. He does not praise all of Asimov's fiction (and nor does Patrouch), but he does call some passages in The Caves of Steel "reminiscent of Proust". When discussing how that novel depicts night falling over futuristic New York City, Gunn says that Asimov's prose "need not be ashamed anywhere in literary society".

Although he prided himself on his unornamented prose style (for which he credited Clifford Simak as an early influence), Asimov also enjoyed giving his longer stories complicated narrative structures, often by arranging chapters in non-chronological ways. Some readers have been put off by this, complaining that the nonlinearity is not worth the trouble and adversely impacts the clarity of the story. For example, the first third of The Gods Themselves begins with Chapter 6, then backtracks to fill in earlier material. (In fairness, one should note that John Campbell advised Asimov to begin his stories as late in the plot as possible.

This tidbit of advice helped Asimov create "Reason," one of the early Robot stories. See In Memory Yet Green for details of that time period.) Asimov's tendency to contort his timelines is perhaps most apparent in his later novel Nemesis, in which one group of characters live in the "present" and another group starts in the "past", beginning fifteen years earlier and gradually moving toward the time period of the first group.

In 2002, Donald Palumbo, an English professor at East Carolina University published Chaos Theory, Asimov’s Foundations and Robots, and Herbert’s Dune: The Fractal Aesthetic of Epic Science Fiction. This includes a review of Asimov's narrative structures that compares them with the scientific concepts of fractals and chaos. Palumbo finds that a fascination with the Foundation and Robot metaseries remains, and he determines that the purposeful complexities of the narrative build unusual symmetric and recursive structures to be perceived by the mind's eye. This volume contains some of the most scholarly and in-depth criticism of Asimov to date.

John Jenkins, who has reviewed the vast majority of Asimov's written output, once observed:

“It has been pointed out that most sf writers since the 1950s have been affected by Asimov, either modeling their style on his or deliberately avoiding anything like his style. In the Hugo Award-winning novella, "Gold", Asimov describes an author clearly based on himself who has one of his books (The Gods Themselves) adapted into a "compu-drama", essentially photo-realistic computer animation. The director criticizes the fictionalized Asimov ("Gregory Laborian") for having an extremely non-visual style making it difficult to adapt his work, and the author explains that he relies on ideas and dialogue rather than description to get his points across. Ironically, the story mimics the same style the author in it uses to describe his work, and one can see it as Asimov's reply to his critics.”

Quotations
"If my doctor told me I had only six minutes to live, I wouldn't brood. I'd type a little faster."

"Writing, to me, is simply thinking through my fingers."

"Night was a wonderful time in Brooklyn in the 1930s. Air conditioning was unknown except in movie houses, and so was television. There was nothing to keep one in the house. Furthermore, few people owned automobiles, so there was nothing to carry one away. That left the streets and the stoops. The very fullness served as an inhibition to crime."

"What I will be remembered for are the Foundation Trilogy and the Three Laws of Robotics. What I want to be remembered for is no one book, or no dozen books. Any single thing I have written can be paralleled or even surpassed by something someone else has done. However, my total corpus for quantity, quality and variety can be duplicated by no one else. That is what I want to be remembered for."

"Violence is the last refuge of the incompetent." Salvor Hardin, a character in Foundation.

"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' (I've found it!), but 'That's funny...'"

"The most hopelessly stupid man is he who is not aware that he is wise" First Speaker, a character in Second Foundation (novel).