Walter Kirn (born 1962) is an American novelist, literary critic, and essayist. He graduated from princeton University in 1983. Kirn is the author of eight books, including Up in the Air, which was made into a movie starring George Clooney, and Blood Will Out, a memoir of his friendship with the imposter and convicted murderer, Clark Rockefeller. he has also reviewed books for New York Magazine and has written for The New York Times Book Review and New York Times Sunday Magazine, and is a contributing editor of Time magazine. In addition to teaching nonfiction writing at the University of Montana, Kirn was the 2008-09 Vare Nonfiction Writer in Residence at the University of Chicago.