Here's a nice account of working for Jack Paar on The Tonight Show by Dick Cavett. Interesting revelation: Paar was very intelligent, but not well schooled, and he was especially conscious of his lack of schooling and envious of people who had what he lacked.

That was true of two other great comedians: Groucho Marx and Woody Allen. I wonder if that quality--self-conscious, unschooled intelligence--is the best source of humor.