“Catch-22” originated as the title of a 1961 novel by Joseph Heller. The original catch-22 in the novel was as follows: a combat pilot was crazy by definition (he would have to be crazy to fly combat missions) and since army regulations stipulated that insanity was justification for grounding, a pilot could avoid flight duty by simply asking, but if he asked, he was demonstrating his sanity (anyone who wanted to get out of combat must be sane) and had to keep flying. The label catch-22 suggested that 21 equally pernicious catches preceded it, but it was catch-22 that caught our attention and entered the language as the label for any irrational, circular and impossible situation.