What is "Catch 22"?

"Catch-22" is a novel by Joseph Heller set in Italy during World War II. The book, which is a satire of bureaucracy and war, employs absurdity and dark humor. It was first published in 1961 by Simon & Schuster.

It is set on a fictional Italian island where a company of bombers are stationed. Catch-22 is an official rule that requires the crew of bombers to fly missions regardless of their mental state. The term has gone on to enter modern English vernacular as a description of any problem whose solution is rendered impossible by the terms of the problem.