About the same time, Mailer had a quick shot at the Bush administration and the fallout from September 11 in The Big Empty, a series of interviews with his son. But that book was merely a break from working on a trilogy of novels that should take in just about every form of evil mankind could engineer.

Mailer usually devotes his novels to the sins and virtues of major players: generals, politicians, killers, athletes and artists. His last novel, The Gospel According to the Son, an exposition of Jesus Christ, is usually cited as his worst. Most writers would take that as advice to slow down. Mailer was inspired to take on the Bible's other lead role, Satan, and one of his malignant earthly monsters, Adolf Hitler.

The first of the trilogy, The Castle in the Forest, opens with narration by Dieter, an SS officer and a mid-ranking devil in the service of the Maestro, who we can only guess is Satan. Dieter is the bad angel assigned to sit on the shoulder of young Adolf and bring out his malevolent potential. He has the ultimate view of the Fuhrer's rise.

'I am ready to write about his early life with a confidence no conventional biographer could begin to feel,' says Dieter. 'It is more than a memoir and certainly has to be most curious as a biography since it is as privileged as a novel. I do possess the freedom to enter many a mind.'

Dieter is Mailer's ideal narrative vehicle. Mailer's non-fiction often leaves the reader wondering whether he believes some of his pronouncements. But in historical fiction he can have his way with the facts. Hitler is a boy born to incest in a family full of sexual misadventure. Mailer recreates everything from the social structures of 19th-century Austria and Germany to the travails of a family.

Dieter never presumes to have simply flicked the switch to Hitler's evil. The child rarely even takes centre stage in his story. He occasionally gives the boy's destiny a nudge but more often watches him take shape in the hands of his bullying, ambitious father, Alois, and his cloistering mother, Klara, who is a little too keen to clean her son's anus. Mailer has always been fascinated with excrement and its delivery system, but here it's elemental to hell. Young 'Adi' witnesses violence for the first time when his father beats the family dog for crapping on the floor. The boy misbehaves by wiping his own on furniture. His most rabid speeches as an adult were punctuated by farts, Mailer reports, and his mother was forced to oblige her husband - and her father's - liking for anal sex.

'The proper study of marriage lies not only in partnership, affection, boredom, verbal scuffles and daily despair, but in the guts and smear of it all, the comradely knowledge of all the forbidden tastes, smells and bodily nooks.'

Mailer's breadth, style and imagination mark him as a great writer. What sets him apart is audacity: he's unafraid to fail. Few writers would have the energy to find anything fresh to say about Adolf Hitler.

In his ninth decade, Mailer has summoned all his skill and experience for a trilogy of enormous scope.