At the heart of Catch-22 resides the incomparable, malingering bombardier, Yossarian, a hero endlessly inventive in his schemes to save his skin from the horrible chances of war.
His problem is Colonel Cathcart, who keeps raising the number of missions the men must fly to complete their service. Yet if Yossarian makes any attempts to excuse himself from the perilous missions that he's committed to flying, he's trapped by the Great Loyalty Oath Crusade, the bureaucratic rule from which the book takes its title: a man is considered insane if he willingly continues to fly dangerous combat missions, but if he makes the necessary formal request to be relieved of such missions, the very act of making the request proves that he's sane and therefore, ineligible to be relieved.