A Conversation with Craig Ferguson

Craig Ferguson is exposing himself. He's rolled up his cuffs to examine a sore spot on his leg where he fell off a horse. ''It was a f---ing Clydesdale as well,'' he says, then adds, ''When you fall off a horse, you should get back on it, but I didn't.'' Which is weird, because the actor, comedian, and Late Late Show host always gets back on the horse. Not always for the better. The first time he drank, he got wildly sick and punched a policeman — so he kept drinking and became a spectacular alcoholic. And when he was chased off stage for his misanthropic comedy character Bing Hitler? He kept doing the character and kept getting chased off stages. American on Purpose, Ferguson's raw, funny new memoir, is full of stories like these, and he rarely fares well in his own telling. ''That's the idea, isn't it?'' he asks. ''It's an autobiography — it might as well be honest.''

And sprawling in scope. Ferguson expounds on his Scottish childhood, his womanizing, The Late Late Show, and more. ''Like most people's lives, [mine] doesn't follow Aristotle's rules of drama,'' he says. Ultimately, the book is about an immigrant's realization that ''Scotland made me what I am and America let me be it.''

Ferguson appears calm for a man whose life is about to be bound and shelved. Will friends take offense at the book? ''I'm sure.'' Will a few celebrities be insulted? ''F--- 'em all.'' He even put a disclaimer in the introduction acknowledging that his recollections may be faulty. The greater sin, he says, would be putting too high a gloss on the past: ''I'm very suspicious of nostalgia. Very suspicious. People go to Renaissance Faires and go, 'I'd love to have lived in medieval England.' I go, 'Really? Think about that the next time you go to the f---ing dentist.