This is his official biography written with the full cooperation of the Pythons and Chapman's partner David Sherlock - with full access to unseen pictures.

Graham Chapman was the quiet, pipe-smoking Python who qualified as a doctor. He was the policeman's son whose tweed-jacketed demeanour belied his true anarchic nature. More than any other Python he lived the complete lunacy of the show. Chapman was John Cleese's writing partner from their early days at Cambridge Footlights right through the Monty Python years. But it was Chapman's off-screen antics that are closest to the surreal qualities of a Python sketch. Terry Gilliam remembers how he would go into a restaurant and suddenly disappear: "He'd be under somebody's table licking the girl's feet while her date was there!"

Chapman was a founder member of an infamous drinking club with The Who's drummer, Keith Moon. Chapman had a wine cellar stuffed full with bottles of gin and at the height of his drinking - which started out as a nerve-calmer for performances - he would consume eight pints of gin a day. He fearlessly flaunted his homosexuality at a time when it was certainly not the done thing. To add further mix to his personal life, Chapman and his partner David Sherlock adopted a 14-year-old boy.

Graham Chapman died in 1989 with brilliant comic timing on the eve of the 20th anniversary of the first recording of Python. A huge celebratory Python party was cancelled as a result and Terry Jones harrumphed Chapman's death as "the greatest act of party-pooping in history". Bob McCabe has had the full co-operation of Sherlock and the Pythons in writing this fascinating and revealing account of the life of one of British comedy's best-loved figures.