JP Donleavy has had me laughing harder than any other author. But it's been many years, and perhaps I've matured since then!
I agree that Mark Twain, Oscar Wilde, Frank Baum, Lewis Caroll and even Shakespeare are quite funny. And not to forget Stephen Leacock, the great humorist. Recently I read Roald Dahl's ''Charlie and the Chocolate Factory'' and enjoyed it a lot.
I must create a system, or be enslaved by another man's. ~ William Blake
Captivity is consciousness,
So's liberty. ~ Emily Dickinson
I'd have to suggest "Three Men in a Boat"- Jerome K. Jerome. I was really surprised at how hilarious it was in parts. Brilliant portrayal of middle-class snobbishness.
I tend to be someone who rarely laughs out-loud at anything particularly the written word. However, Adams, Spark, Waugh and Heller, I find terribly funny.
A Confederacy of Dunces - Kennedy
Catcher in the Rye -Salinger
The two funniest books that I can recall.
I have read two plays of George Bernard Shaw and thoroughly enjoyed them, especially Arms and the Man. It is not just funny but witty too.
Maybe its just me, but I burst into laughter at least once each chapter when reading Don Quixote. When he charges the flock of sheep and gets stoned by the shepherds, oh my, how I chuckled at that.
Confederacy of Dunces, any Vonnegut novel & Catch 22 are good calls. I just finished White Noise (Delillo) which definitely had its moments; as did Notes from the Underground (while not known as a side splitter it certainly can get you rollin').
http://unidentifiedappellation.blogspot.com/
Don Quixote really is pretty damn funny.
I also thought that Dorian Grey was hillarious, but that's just my sense of humour. I loved Dorian, I thought that he was a riot.
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"Personal note: When I was a little kid my mother told me not to stare into the sun. So once when I was six, I did. At first the brightness was overwhelming, but I had seen that before. I kept looking, forcing myself not to blink, and then the brightness began to dissolve. My pupils shrunk to pinholes and everything came into focus and for a moment I understood. The doctors didn't know if my eyes would ever heal."
-Pi
Vonnegut and Douglas Adams have a flair for wit. But, I'd say that Catch 22 is the rare book that had me turning heads as a result of my seemingly random laughter.
Byron's Don Juan, had me laughing out loud every stanza