Short Summary
Captain Joseph Yossarian, a World War II bombardier, is being stationed on the island of Pisona. He is an individualist who seeks to protect his own life by fleeing to the hospital, since catch-22 prevents him from either being grounded for illness or obtaining a leave. He enjoys living the ward; all his meals are served to him, and in turn, he simply needs to feign having pain in his liver and censor letters of enlisted men. Bored by his job, Yossarian takes on the pseudonym ìWashington Irvingî and even pretends to be Chaplain Tappman once. Alarms are raised, and the government sends two C.I.D. men to investigate. Other men also seek the haven of the hospital by feigning illness, but after the mysterious death of one of their colleagues, the soldier in white, the Texan forces them to return to the front.

At the front, the other men are equally as crazy as Yossarian. His roommate, Orr, constantly crash-lands every time he goes on a mission and enjoys talking about putting apples or horse chestnuts in his cheeks. Clevinger, a Harvard graduate, argues with Yossarian about whether people must obey their institutions and fight the war. Havermeyer munches on peanut butter brittle all the time, loves to shoot innocent field mice with his 0.45, and never takes evasive action on a mission, earning the wrath of his men. Doc Daneeka, the squadron's doctor, is a hypochondriac who belittles everyone else's illnesses rather than treating them, and bemoans his own troubles. Chief White Halfoat brags about his displacement by ìAmericansî because they strike oil wherever he and his family go and constantly gets drunk. McWatt, Yossarian ës brainless pilot, drives Yossarian up the wall by flying his airplane a few inches right above Yossarian's tent. Hungry Joe has screaming nightmares, although he denies it each morning, and fistfights the cat that belongs to his roommate. Chaplain Tappman, along with his assistant, has been ejected from the Officers' Headquarters and spends his time peacefully in the woods on the periphery of camp. He tries to stand up against Colonel Cathcart for Yossarian, but is too spineless. His assistant, the atheistic Corporal Whitcomb, constantly abuses the chaplain and collaborates with Colonel Cathcart to have the chaplain court-martialed.

In protest against being forced to fly more than the required number of missions as designated by the Group Headquarters, Yossarian uses various strategies. At the beginning of the book, he flees to the ward and discovers what a haven it is. To prolong his stay there, he pretends to have a strange disease in which he sees everything twice. In combat, he takes evasive action during his flights to avoid being killed. He also turns back once, pretending that his intercom is defective. When Colonel Cathcart volunteers his squadron for the dangerous Bologna mission, Yossarian moves the bombline on the map to deceive the men into thinking that it has already been captured and the air strike is called off. Despite these tactics, he cannot avoid combat entirely and is haunted by the death of his comrades. At Avignon, Snowden is killed, and Yossarian has terrible memories of his attempt to save Snowden, although . After this traumatic experience, he walks around naked, without his uniform, and watches Snowden's burial from a tree. Then, an otherwise unknown man, Mudd, is killed just two hours after his arrival and is dumped in his tent. Everyone denies the existence of Mudd, so he lies there, despite Yossarian's protests. The final straw, though, is when his dear friend, Nately, is killed at. After this, Yossarian refuses to fly any more missions.

When they realize that Yossarian cannot be dissuaded, the officers try to make a deal with Yossarian that will allow him to no longer fly any missions but be ethically repulsive to him. They will send him home as long as he likes them. If he does not give in, he will be court-martialed for being involved in black market practices. Yossarian protests against such wrongful accusations, but the officers claim they are justified in jailing an innocent man to keep the war effort going. Left without any other choice, Yossarian runs away to avoid court-martialing as well as Nately's whore, who is trying to kill him to avenge Nately's death.