Hitch-22: a memoir by Christopher Hitchens

Janus, the Roman god of gates and beginnings, is the presiding deity of Christopher Hitchens's memoirs, for his ability to look back and forth simultaneously.

"I hope," says the author in a prologue, "to give some idea of what it is like to fight on two fronts at once, to try and keep opposing ideas alive in the same mind, even occasionally to show two faces at the same time."

It's a risky strategy, this flirting with two-facedness, but Hitchens has never been afraid to confront his detractors. They call him a three-bottles-of-Champagne-and-a-brandy-chaser Socialist; a political tourist, available to report from any display of Marxist posturing; a fellow-traveller of the hard left who lurched unforgivably right when he supported Bush's invasion of Iraq; a louche, lecherous lush masquerading as a political sage.

Hitch-22 is a 420-page apologia pro vita sua in which the personal and the political are constantly entwined. The early chapters offer wonderful evocations of his parents. His adored mother, Yvonne, served as a Wren in the war and met his father Eric, a naval Commander, in 1945.

Hitchens's first memory was of the massive harbour in Malta, where his parents were stationed. Yvonne loved the club-and-cocktail circuit there, and was dismayed by the family's move to Scotland's grim east coast.

Determined that her favourite son should be "one of the upper class", she sent him to boarding school at eight to become an English gentleman. She opened dress shops, embraced early new-age fads and Kahlil Gibran, and left the Commander for an ex-clergyman called Timothy, with whom she made a suicide pact in an Athens hotel room. Hitchens's memory of going there to recreate her last hours is affecting: she introduced him to poetry and pizzazz and represented his "first and truest" identity.

His father was purse-lipped and silent, resentful of the post-war running-down of the Navy and empire, fuming at the Admiralty's betrayal of its pensioned-off heroes. But in his gruff way he admired his son's journalism, while his son admired "his lack of guile and his dislike for anything that was surreptitious or underhand." You can infer mixed feelings from the author's fondness for this disappointed imperialist.

Hitchens's schooldays read like a primer in How to Achieve a Radical Conscience. A voracious reader, he was bowled over by How Green Was My Valley for its idealised Welsh miners, Tawney's Religion and the Rise of Capitalism (read, slightly unbelievably, at 14 to beguile the boredom of chapel), Darkness at Noon, Crime and Punishment and, inevitably, Orwell: "I hadn't quite appreciated that actual fiction could be written about morose, proud but self-pitying people like us."

Disdaining the Leys school's cadet force, he became its representative on the United Nations Association's Cambridge schools committee. From this lowly induction into organised debate he never looked back. By 1966, aged 17, he was demonstrating in Trafalgar Square against the Vietnam War. A year later, at Balliol College, Oxford, he joined the International Socialists.

Under the influence of Peter Sedgwick, he discovered a left-wing elite within the left: anti-Stalinist, Trotskyite, endlessly challenging easy orthodoxies of pro-Soviet or pro-Cuban idealism. This section forms the emotional heart of a mostly unemotional book. We hear nothing of love affairs, of personal epiphanies, issues of self-esteem or intellectual inadequacy. Instead we get Hitchens the radical action man, selling Socialist Worker and spray-painting pro-Vietcong graffiti by day, debating at the Oxford Union by night and discovering the joys of donnish indulgence. Taken up by dazzled left-wing history dons, he found he could invite heavyweight thinkers (such as Isaiah Berlin) to speak at the Labour Club and inspect them at close quarters. Being Hitchens, he confesses to being "amazed at how ignorant and sometimes plain stupid were the people who claimed to run the country."

Suave" is perhaps the best word to describe his prose style. No matter how noisy the buzz of the late-1960s revolutionary movements, no matter how passionate the warring ideologists, Hitchens always contrives to sound detached, loftily appreciative, self-admiring, as much at home fondling a leather-bound wine list as a Marxist tract. I admired his restless travelling to political zones and danger areas (Prague, Havana) but that languid voice undercuts his very real achievement.

Visiting Belfast with James Fenton, and ill-advisedly venturing down the Falls Road, he witnesses a nail-bomb being thrown at a British patrol, and drops to the gutter. Then: "Rising too soon from my semi-recumbent posture, I found myself slammed against the wall by a squad of soldiers with blackened faces, and asked various urgent questions... Managing a brief statement in my cut-glass Oxford tones, I was abruptly recognised as non-threatening, brusquely advised to fuck off, and off I duly and promptly fucked." The nods to Lady Bracknell and PG Wodehouse seem, in the circumstances, to mark our hero as a bit of a chump, rather than a Graham Greene-ish voyager on the dangerous edge of things.

In London, he discovers Martin Amis – who seems to have been his first real friend, not a political ally, ideological scratching-post or sexual prospect – and the book's atmosphere lightens. "Hitch" also discovers Bloomsbury, Soho, journalism, the New Statesman, whisky, laughter and boyish word-games at agreeable lunches with the literary gang of the late 1970s. His compulsion to over-share, as they say in New York, goes into over-drive here. Having confided his gay frolics at school, and his polymorphous appeal to all sexes, he ponders that, when he went to bed with Amis's sister Sally, it might not necessarily have been out of transferred lust for Martin.

These too-much-information moments are, however, welcome revelations of feeling that peep out from behind the louche carapace. The years up to 21 take up half the book. The remainder, covering his exile to New York, then Washington, are less exciting. His account of 9/11 – he was in Seattle at the time – is a little muted, though it's instructive to find it was his indignation at the world's lack of sympathy with America that bounced him into applying for US citizenship.

The Rushdie fatwa brings out the combative best in his writing; his call for "a bit of character and guts and integrity," his willingness to put himself in the firing line, his lack of patience with anyone who doesn't feel like joining him. His musings on Islamophobia and the need for executive action against Saddam Hussein read too much like essays – until he tells the story of Mark Jennings Daily, a young Californian who went off to Iraq to fight, and die, for a war in which he believed because of Hitchens's writings.

Initially mortified by the moral burden, Hitchens links up with Daily's family and evokes the soldier's life with heartfelt tenderness. It's the emotional highlight of an extremely beguiling book - by turns passionate and defensive, argumentative and seductive – from a man who stood several times at the gate of history and was never satisfied with what he saw.