His interviews are compiled in a new book, "Sick in the Head."
Jay Leno is king of late-night TV ratings, but Jimmy Fallon could represent the future of the TV franchise. He has strong ratings plus a big You Tube and Twitter following that advertisers care ever more about.
Half a billion dollars of advertising is at stake in what is now a three-way competition among Jay Leno, Dave Letterman and Jimmy Kimmel. One show's response to Kimmel's challenge: shave a minute off its start time.