Asbestos pants are all part of a nun-like life

For some of us, the discovery that Terry Eagleton is the author of a personal memoir is as surprising as learning that Mike Tyson is a closet ballet dancer or the Queen the newest cool DJ on the club circuit. This is, after all, the man who has consistently questioned the ideological purpose behind the literary biography. "The structure of biography is biology," he wrote disparagingly some eight years ago. "Even the most wayward of geniuses have to get themselves born and educated, fight with their parents, fall in love and die." The biography is hidebound by the bourgeois idealisation of the individual, by the conservative celebration of an essential human nature that is impervious to the external pressures of political progress. Too much namby-pamby introspection and not enough tough Marxist dialectic.

But when you dip into The Gatekeeper , you find that Eagleton has produced a masterpiece of anti-biography, a flagrant subversion of the cosy kiss-and-tell. It is as riveting and disturbing a challenge to generic expectations as if Jonathan Swift's Modest Proposal were to be sold as a nursery guidebook or Jane Austen's Pride and Prejudice as a raunchy sensation.

Instead of confiding the intimate secrets of his life, Eagleton fills his book with the people he has encountered - a Dickensian cast of characters. Self-mortifying Carmelite nuns, tipsy priests who have to sleep off the Eucharist, the Salford working class who keep their front room "for the best" and therefore nothing ever happens there, eccentric Oxbridge dons who believe studying English literature is all about the stomach muscles (affecting how one declaims it), Mormon men clandestinely sporting asbestos underpants designed to survive the apocalypse, and braying aristocrats who own half of Aberdeenshire: it is a heady, hilarious mix.

Behind the deflecting jokes, however, it is possible to detect some serious thinking, chiefly about the culture of radicalism. Eagleton believes that radical socialism springs from the same roots as the fervent Catholicism in which he was raised. Like the Catholics, radicals do not waste their concerns on the practicalities of the here and now but resolutely pin their hopes on a future utopia, whether that be heaven or an utterly unrecognisable, classless Salford. Like Catholics, too, radicals believe in being martyrs to a cause; the Carmelite nuns who incarcerated themselves away from the world in virtually a living death were not so far removed from revolutionaries who recognise "the kind of drastic self-abandonment which the world would need if it were to become just". Finally, like the Catholics, radicals do not believe in sentimental personal feeling or self-analysis. Both movements involve activity rather than agonised reflection and the collective rather than the closeted individual. Eagleton's close involvement with the Catholic left and its journal Slant in the 1960s emerges, therefore, as central to understanding his politics.

If Catholics, for all their bizarre and lovingly recalled quirks, turn out to be fellow-travellers, leftwing liberals certainly do not. Earnest feminists, well-meaning liberals and trendy postmodernists earn more opprobrium in this book than a puritan in Las Vegas. Their mistake is to compromise, to see both sides of the argument and to stand judiciously in the middle, to celebrate the plurality and diversity of life. In effect, they accept the world roughly the way it is and, as such, Eagleton believes, they are in hock to the world of global capitalism. Their only hope is to make that world a little better, to understand its inhabitants a little more sensitively. In contrast, the radical socialist is militant, totalitarian, universalising and materialising, committed to wholescale apocalyptic revolution. It is a compelling distinction, flawed only by Eagleton's own ambivalence about commitment. He confesses, as an activist "by conviction rather than temperament", to preferring Proust to picketing. And he feels a closer affinity with the aristocracy, dispossessed from society by their uselessness, than he does with a well-intentioned middle-class deliverer of meals-on-wheels. If the world divides, as Eagleton suggests, between the Good and the Fine, between those who do things for a greater cause and those who are fun to be with, then he is caught between the two, reducing virtue or conscience to a literal absurdity yet pained by the political abrogation of his generation.

So The Gatekeeper is supposedly about radicalism but ends up paradoxically, despite appearances, being more about Terry. It goes some way in considering the present failure of the socialist cause. But it goes further in exposing the contradictions, evasions, confusions and comical excesses of one of its supposed leading exponents. I loved it.

Jennifer Wallace is a fellow of Peterhouse, Cambridge.