Those of us who are not celebrities undoubtedly cannot imagine the temptations that beset those who are. If you’ve written more than thirty books, several of them bestsellers, a few acclaimed as classics, a couple made into movies; if you’ve been everywhere in the world; if you know everyone in English and American literary circles; if beautiful strangers regularly fall for you, it must be hard not to assume that anything you write is sure to be interesting. It is a dangerous assumption.

But not invariably a mistaken one. The novelist and travel writer Paul Theroux, for example, probably couldn’t write an uninteresting book, even about a subject as unpromising as the life of a novelist and travel writer named “Paul Theroux,” who has published several books with the same titles as Paul Theroux’s books, has grown up and lived in the same places at the same times as the real Paul Theroux, and has two sons the same ages as Paul Theroux’s two sons and a wife from whom (like Paul Theroux) he was recently and painfully divorced.

Actually, he (Paul Theroux, that is) has just written a book about this very subject, called My Other Life. “This is the story of a life if could have lived had things been different -- an imaginary memoir,” he declares in a coyly obfuscatory “Author’s Note.” “The man is fiction, but the mask is real.” I don’t know exactly what that means, and quite possibly Theroux doesn’t, either. But it doesn’t much matter. My Other Life has style and feeling enough to engage even those who don’t care whether “Paul Theroux” is Paul Theroux and haven’t a clue what an “imaginary memoir” is.

The nineteen chapters of My Other Life do not quite stand alone, but almost, like solos in a long jazz number. The opening riff, “Uncle Hal’s Other Life,” adds to Theroux’s gallery of memorable eccentrics. Like Allie Fox in The Mosquito Coast,Uncle Hal is a force of nature: omnicompetent, zany, paranoid, unkempt, weirdly erudite. He disappears, to the family’s relief, but years later a novel appears, “a masterpiece of sanity and elegance.” Moral: the novelist is a trickster. As usual in Theroux, wistful hints about the mysteriousness of art fall flat while details and dialogue take wing.

In “The Lepers of Moyo” a Peace Corps volunteer teacher in Nyasaland spends his vacation working at a Catholic leper hospital. His English class is a failure, he nearly dies of fever, and the only white woman at the hospital (except for the nuns) repels him; but a pretty young leper captivates him and, in a wittily sensuous scene, takes him into her bed. It is Graham Greene-land: the worldly Father Superior and the earthy lay brother play cards; the devout, high-strung younger priest broods and eventually breaks down. But if it is less taut and philosophical than Greene, it is also more brightly lit and thickly described. The Africans are neither noble nor ridiculous but genuinely exotic; and Theroux’s ear for their pidgin English and for the music of their Chinyanja language is a joy.

The freshness of this African chapter dissipates gradually as Theroux returns to civilization. But it’s a roundabout trip: first comes a stint in Singapore (“buses, hawkers, rickshaws, shouts, stinks, glaring lights, and air like a dog’s breath that stuffed your head with humid heat”). He teaches for a pittance at the university, then tutors a wealthy European businessman who dabbles in poetry. The businessman’s jaded wife makes a grab for Theroux, ending his stay on the island.

White women are a problem altogether for our (fictional) hero. They harry him. An interviewer turns out to have appeared briefly, unflatteringly, in his The Great Railway Bazaar and now, a dozen years later, shrieks her resentment. In a remote English coastal town, a woman in a pub invites him home; without knowing his identity, she praises his books; he hesitates, leaves still incognito, and later learns she was a psychopath who has killed two former lovers. He meets one of his own former lovers, who worries the old bones of their relationship so relentlessly that he is driven to seek out (incognito again) and befriend her ex-husband. And there is the unforgettably depraved Lady Max, a rich London literary vampire. (Someone in London is surely gnashing her teeth and plotting revenge at this very moment.) Unexpectedly, though, he is half-charmed by Queen Elizabeth: “Yes, God the Mother would look something like this -- muffin-faced, crinkly, twinkling, small and dumpy, but also diamond-studded, bossy, and appreciative and willing to please.”

The woman who gets most deeply under his skin is his wife, with whom he is still, after twenty years and a number of infidelities, very much in love. His description of their domestic happiness is lyrical; his account of their separation is heartbreaking; his subsequent long depression is bleakly convincing. Theroux may be a cad (or so his brother, the novelist Alexander Theroux, claimed recently in an unbelievably splenetic essay in Boston Magazine). But although many scores are settled in My Other Life, the book is also a long, tender, and apparently sincere valentine to his ex-wife.

For those of us who still haven’t a clue to what an “imaginary memoir” might be, Theroux has obligingly slipped one in. “A writer often chooses to leave a chapter out of a book,” one chapter begins. But “writers are careful not to throw anything of value away. The fact is, no matter how bizarre or scandalous, the sunken chapter always surfaces.” I suspect that My Other Life -- at least the many bizarre and scandalous bits -- is a collection of Theroux’s “sunken chapters.”

A throwaway book, in other words; a mere jeu d’esprit; a ragout of gossip, malice, and inside jokes. Still, one writer’s jue d’esprit is another’s tour de force. By now Theroux’s story-telling is so well-practiced, his eye and ear so keen, that even at half-throttle, as he is for much of this book, it’s a lively ride.