Michael Shermer (born in Glendale, California) is a science writer, historian of science, founder of The Skeptics Society, and editor of its magazine Skeptic, which is largely devoted to investigating pseudoscientific and supernatural claims. Shermer also produces and co-hosts the 13-hour Fox Family television series, "Exploring the Unknown," and is a monthly columnist for Scientific American magazine. Shermer was once a fundamentalist Christian, but according to his book The Science of Good and Evil, is now an agnostic and an advocate for humanist philosophy.

Michael Shermer received his bachelor's degree from Pepperdine University in 1976 in Psychology/Biology, his master's degree from California State University, Fullerton in Experimental Psychology two years later, and his Ph.D. from Claremont Graduate University in History of Science in 1991 (with a dissertation entitled "Heretic-Scientist: Alfred Russel Wallace and the Evolution of Man: A Study on the Nature of Historical Change").

Shermer is the author of several books that attempt to explain the ubiquity of what in his opinion are irrational or unsubstantiated beliefs. Why People Believe Weird Things, treats a variey of "weird" ideas and groups (including cults), in the tradition of the skeptical writings of Martin Gardner. He has devoted entire books to Holocaust denial (Denying History, coauthored with Alex Grobman), and to belief in God (How We Believe).

In 2004, he appeared in a second season episode of Showtime's popular series Penn & Teller: Bullshit! called The Bible: Fact or Fiction?, which sought to debunk the notion that the Bible is an empirically reliable historical record. Opposing him was Dr. Paul Maier, professor of ancient history at Western Michigan University.

Shermer is also a cycling enthusiast and was once a marathon bicycle racer; he helped found the Race Across America and competed several times. He has produced over a half dozen documentaries on cycling.