This is the funniest book ever written. Ever. It's not as if I haven't read comedy before, but this book takes satire and comedy to a level untouched before.
The story revolves around the escapades of a U.S. Air Force bombardier by the name of Yossarian during the final stages of WWII, mostly on the Mediterranean island of Pianosa.
The book is satirical in every way, with the majority of criticism revolving around the bureaucratic functioning of the military. Throughout the book the concept of a parodoxic situation in which no option can be the winning option, or a "catch 22" as it is now popularly known, is made use of in many hilarious scenes. There is no way to aptly describe the meaning of a "catch 22", so I'll use the words of Heller himself:
There was only one catch and that was Catch-22, which specified that a concern for one's safety in the face of dangers that were real and immediate was the process of a rational mind. 'Orr' was crazy and could be grounded. All he had to do was ask; and as soon as he did, he would no longer be crazy and would have to fly more missions. Orr would be crazy to fly more missions and sane if he didn't, but if he was sane he had to fly them. If he flew them he was crazy and didn't have to; but if he didn't want to he was sane and had to. Yossarian was moved very deeply by the absolute simplicity of this clause of Catch-22 and let out a respectful whistle.
"That's some catch, that Catch-22," Yossarian observed.
"It's the best there is," Doc Daneeka agreed.
There you have it folks, "catch 22" straight from the source. This nightmare of bureaucratic mazes is endured by Yossarian and his friends throughout the book, resulting in one horrific experience for them, and one reading experience that will have you aching with laughter. I cannot recommend this book enough. All I can say is that I've read it over a dozen times and I still laugh at every page.