Yossarian is in the hospital with a supposed case of almost jaundice. It is supposed because he knows he is cured and it is almost jaundice because it never turns into total jaundice. He is in the hospital for self-preservation. As long as he is there, he does not have to fly anymore bomber missions and thus his life is not in peril. He meets multiple other soldiers there, most of whom are committing the same scam he is. They will do anything to keep from going back into battle.

The officers are required, while at the hospital, to censor the letters of the enlisted men. Yossarian uses his powers as censor to have a little fun by censoring the letters in an unusual and incorrect manner. He starts to sign his name to each letter as "Washington Irving". This draws the attention of the commanders and a C.I. D. man is sent undercover to find out who this "Washington Irving" is. Fortunately for Yossarian he leaves the hospital before he is found out.

Yossarian shares a tent with Orr, and they are compatible tent mates. Orr thinks up ideas in order to make the tent more homelike and Yossarian implements the plans. Another member of the squadron is Clevinger. He and Yossarian are begrudging friends. Yossarian believes the enemy is out to specifically kill him. Clevinger thinks that Yossarian is crazy because he feels the enemy is out to kill everyone not just Yossarian. After all, it is a war they are fighting and so the aim is to kill the people on the opposing side. Yossarian knows he is right and that Clevinger is wrong. Yossarian thinks everyone who is fighting in the war is crazy.

The other problem faced by Yossarian and all the other men is the number of missions needed to be eligible to go home. The commanding officer keeps raising the number and the men are fed up with it. They survive the required number of missions and think that they are going home only to be informed that the number of required missions has just been raised.

In chapter three we learn more about Orr, how when he was a kid he would walk around with crabapples in his cheeks. He did this in order to have apple cheeks, the round cheeks which were considered appealing in his youth. We also find out about an incident he had with a prostitute in Rome. It seems he did something that so upset the woman that she hit him multiple times until she knocked him unconscious, and no one ever knew why.

In order to help the men deal with the tedium they faced between bombing runs, General P.P. Peckem would send U.S.O. troupes to entertain the men. He did this for two reasons. One was to make sure his presence was felt by the men, and two was to cause problems for General Dreedle. General Peckem and General Dreedle did not get along. General Peckem wanted everything done his way, whereas General Dreedle had a propensity to ignore General Peckem's orders. This was because General Peckem's orders were often nonsensical, such as the order to have the men's tents all facing the direction of the Washington Monument. General Peckem sent Colonel Cathcart to make sure the men attended the U.S.O. performances. Cathcart ordered the men to attend the performances.

Yossarian often went to his friend Doc Daneeka with the request to be grounded, but the doctor always refused. He told Yossarian to be like another soldier named Havermeyer who never took evasive action to avoid being hit, but instead always flew directly at his bombing target. He was the best bomber in the squadron. He was also the least liked because of his dangerous actions, whereas Yossarian was well liked because he was best at evasive action. Havermeyer also took delight in killing mice with his gun. One night his gun fire woke Hungry Joe, who ran from his own tent to Havermeyer's and shot up the tent with his own gun.

Hungry Joe had flown so many missions that he was left in a constant state of anxiety, which manifested itself as nightmares that left him screaming and yelling into the night, every night. Yossarian talked to Doc Daneeka about Hungry Joe's problems, but the doctor did not have any sympathy for Hungry Joe. He was instead focused on his own problems which entailed having to leave his medical practice and needing to log flight time each month. When he was drafted his medical practice was finally starting to make money. Flight time was his other problem. The doctor was afraid of flying, but he had to have flight time in order to receive flight pay.

In chapter five Yossarian asks if he were declared crazy if he could then go home. The problem is the Catch-22 clause, which in essence states that if you are able to tell someone you are crazy, then by the act of realizing you are crazy makes you sane enough to fly. But, if you are crazy and do not tell anyone you are crazy then you still have to fly because no one knows you are crazy.

Hungry Joe fit the Catch-22 definition to a tee. He was, in fact, crazy but he did not recognize it nor would he admit it, so he kept on flying. Chief White Halfoat also was a bit unhinged. He kept his tent mate in terror because one night he told Captain Flume he was going to cut Flume's throat while he slept. Flume spent the rest of his time trying to never fall asleep.

The beginning of Catch-22 shows us the lengths the men will go to go home. Heller is trying to show us the illogical world that the men live in and introduce us to the main characters in chapters one through six.