Daniel Martin Klein (born 1939 in Wilmington, Delaware) is an American writer of fiction, non-fiction, and humor. His most notable work is Plato and a Platypus Walk Into a Bar co-written with Thomas Cathcart.
Klein went to school at Harvard College where he received a B.A. in philosophy. After a brief career in television comedy, he began writing books, ranging from thrillers and mysteries to humorous books about philosophy, including the New York Times bestseller, Plato and a Platypus Walk into a Bar: Understanding Philosophy Through Jokes (with Thomas Cathcart). He lives in Great Barrington, Massachusetts, and is married to Freke Vuijst, American correspondent for the Dutch newsweekly, ‘Vrij Nederland’. Their daughter, Samara Quirine Klein, is Director of Rights and International Operations for the PJ Library at the Harold Grinspoon Foundation.