“The best spy novel of all time.” That’s what Publishers Weekly called “The Spy Who Came in from the Cold” in 2006, forty-three years after the book’s publication. John le Carré’s international best-seller is dynamite—fiendishly clever, as Arthur Conan Doyle might have said, and morally alert in a way that puts it way above the usual run of espionage fiction. Yet it’s not le Carré’s masterpiece. The author, born David Cornwell, wrote it at the peak of the Cold War, and he made the startling decision to portray the intelligence methods of both Western and Communist countries as vile and morally senseless. By this, his third book, he had found his great theme, betrayal, which he has dramatized with infinite variation ever since. The plot depends on a series of reversals—as you read, you have to revise your understanding of what’s going on, which is part of the fun—but, in the end, all mysteries solved, “The Spy Who Came in from the Cold” seems as schematic as an architect’s drawing.

The book reproduced the East–West conflict as a set of obscure, fascinating, and dubious strategies. Who gained from the complex role-playing? The double agents, the planted insinuations, and the endless treacheries? What was won? After reading le Carré, you may think that the struggle against Communism is still necessary, but only a fool would think of it as anything but sordid. For some of us, this bleak and witty thriller was an introduction to grownup reality. No pessimistic book ever gave as much pleasure.

Yet the question of which is le Carré’s best book remains in play. Certainly, “Tinker Tailor Soldier Spy,” the first of the trilogy later known as “The Quest for Karla” (which includes “The Honourable Schoolboy” and “Smiley’s People”) is the most entertaining of le Carré’s books. It came out in 1974, when everyone still remembered how badly British intelligence had been compromised in the forties, fifties, and sixties by Soviet double agents like Kim Philby and Guy Burgess. The scandal was still alive. (Sir Anthony Blunt confessed in 1964 that he had worked for the Soviets, but he was at large in the seventies. Margaret Thatcher didn’t reveal the truth about him until 1979.) In “Tinker,” le Carré tells us very little about how treason begins, but he creates a fictional account of how it might be shut down. As all the world knows, the meek-mannered cuckold George Smiley, roused from retirement and disgrace, uncovers a mole in M.I.6. (the Circus) by setting traps so intricate that only a spy could fall into them (funny, in its way).

Like Raymond Chandler, another so-called genre writer (in this magazine, Pauline Kael once described Chandler as a skilled creator of pulp), le Carré offers a specialized view of life, but one so persuasive that many readers begin to see things in his ripely jaundiced way. Chandler was a master of the sleaze and alluring amorality of Los Angeles. Le Carré recorded the club banter—suave, heartless, knife-edged—of educated Englishmen drawn to espionage. He created the cryptic jargon of tradecraft—lamplighters, scalphunters, babysitters, joes, mothers, burnboxes—some of which got taken up by actual spies. In his masterpiece “Kim,” Kipling did the same for the lingo of Russo-British rivalry (“the great game”), but Chandler and le Carré devised, as they say, an entire world, increasingly detailed and comprehensive, a joy for adepts and for the quickly initiated. By the mid-seventies, however, the author of “genre books” was obviously a major novelist who understood the complications of deceit and self-delusion as well any writer.

Some time after “A Perfect Spy” came out, in 1986, Philip Roth remarked that it was “the best English novel since the war.” So that was le Carré’s greatest book. Yet many were puzzled. Since the war? That would cover at least forty-one years, and works by George Orwell, Kingsley Amis, Angus Wilson, Graham Greene, Muriel Spark, Anthony Burgess, and Anthony Powell. Still, I was willing to trust Roth’s judgment, so I began to read. And, on two separate occasions, I found “A Perfect Spy” so densely worked and allusive that I fell out of the saddle, slightly embarrassed, after about fifty pages. But redemption lay at hand. A couple of months ago, prepping for a movie review, I read le Carré’s excellent late novel, “A Most Wanted Man” (2007). The toughness and complexity of that book re-launched me into “A Perfect Spy.” And it turns out that Roth was right.

The perfect spy is one Magnus Pym, a name that suggests a man who is somehow both superlative and ordinary. It’s the late seventies or the early eighties, the Cold War is winding down, and Magnus is in the twilight of his career. His mentor in London—the extraordinary spymaster Jack Brotherhood—wants to believe in him, but the rest of what used to be called M.I.6. (now S.I.S., or the Firm) has suspected for years that Pym is a double agent. London, leaving him at large, posts him to Vienna, a relative backwater for espionage. In all, British intelligence, including Magnus, seems less concerned with Communist espionage than with the possibility that the well-funded C.I.A. will muscle in on British operations.

That goes for le Carré, too, who has always been scornful of American spying. The Americans lack style, subtlety, patience. They burst forth from an incoherent, mongrel society, innocent of family and tradition and manners—every lack that Henry James complained of a hundred fifty years ago—before departing for London. Worst of all, they fail to enjoy spying as a treacherous game; they think they are saving the world, whereas the Brits know that, apart from Britain’s dwindling interests, there’s nothing to be saved, just the endless struggle itself, well or poorly joined. Among other things, “A Most Wanted Man,” set in Hamburg in the mid-aughts, is an outraged protest against American blundering after 9/11.

At the beginning of “A Perfect Spy,” Magnus suddenly and silently disappears, retreating from Vienna to a tiny English boarding house near the sea. He wants to write—about his life, his career as a spy, his loyalties and betrayals. He wants to make an accounting for himself and for his splendid teen-age son, Tom. Now, as far as I know, le Carré has never been called an experimental or modernist writer. (It’s very unlikely that Susan Sontag would have been interested in him.) But “A Perfect Spy” is actually a meta-fiction. It’s about a man writing his life—in effect, writing a novel—and the text that Magnus produces is frequently coy and unreliable, which makes the complexities of the book staggering. There are overlapping tales, stories within stories, ricocheting versions of Magnus’s career. Le Carré doesn’t just stick to Magnus Pym’s discourse; he offers the point of view of Jack Brotherhood and of Pym’s staunch and frightened wife, Mary, both of them trying to find the missing man while worrying through their memories of him. Jaunty and comprehensive, le Carré jumps around in time, recounting Magnus’s life as son, lover, husband, embassy social lion, and spy.

Most of all, as son. Magnus wants to finally unload his obsession with his father Richard (Rick) Pym, a swindler, liar, scoundrel, and enchanting son of a bitch; a Falstaff who does genuine harm. Rick screws people, and they almost always come back to him. He’s where the action is, right up to the end of his life, and Magnus adored and imitated him, becoming not a criminal but a professional con man and teller of tales, an agent. Like Rick, he betrays everyone, which is why he’s “perfect.”