I started skimming this for 30 minutes, just as I was leaving a library in Croatia. Other reviews tell me there's a good deal of (warranted?) character assasination in the book, but hovering around the beginning of the book, I somehow snatched the meat. Heller was an advertising exec who'd grown up visiting the Jewish vaudeville centers in the Poconos. That helped explain his amazing ear for words and his ability to make the ridiculous sublime.
But truth be told, it appears to have been his editor working with him over the manuscript, rewriting it again and again, which helped tone down the humor and turned it into a "serious" book.
Strange to say, although not apparently mentioned in this book, the same editor rejected rewrites of "Confederacy of Dunces" numerous times for being too funny or pointless, which is said to have lead to O'Toole's fatal depression. Catch-22 is the better book, but I can's see why being incredibly funny is any kind of demerit.