Single & Single

Though the end of the Cold War has been nothing short of a career catastrophe for most writers of spy fiction, John le Carre continues to soldier on. He may not sell as many books as he once did, but he continues to write convincing and inventive ones. In fact, the chaotic, ''be careful what you wish for'' triumph of free-market economics seems to have revitalized him. Even his prose, which could remind you sometimes of Henry James at his most ponderous, is leaner, faster. In Single & Single, a clever (but not, thank goodness, infernally clever) plot about a London bank that launders drug money quickly sets up a good old-fashioned chase story, the kind where a reluctant but resourceful amateur goes after a gang of bad guys.

When a lawyer employed by the House of Single, Alfred Winser, is murdered in the Turkish hills, his boss, Tiger Single, goes on the lam, terrified that he'll be the next target. That's because two of Alfred's more slippery clients — aging Georgian patriarchs Yevgeny and Mikhail Orlov, along with their gunman, Alix Hoban — believe that Tiger has sold them out to Her Majesty's Secret Service. Meanwhile, the old financial buccaneer blames the treachery on his only son, Oliver, who dropped out of sight four years earlier. Having disowned his unscrupulous father, he's living in a small English coastal town as ''Ollie Hawthorne'' and earning his living as a children's magician. But in the wake of Tiger's disappearance, he returns to London.

Without a lot of enthusiasm, Ollie decides to locate his father before Tiger's enemies do. So it's off to Zurich, then to Istanbul, and finally into the hill country of Russian Georgia, where almost everybody is surly and carries an automatic rifle. Le Carre's novels have never been known for their rip-roaring action, and this one, up until the final two or three pages, doesn't go against type. What's most gripping is the long set pieces, the interrogations and conversations in places as exotic as a dilapidated mansion overlooking the Bosporus or as soulless as a lawyer's office in Switzerland.

And as usual, Le Carre manages to give his characters (everyone except the loathsome Hoban, who's just your quintessential monster) an extra something, some idiosyncratic element that lets them transcend their genre roles. This time he's especially good with the minor players — a young Russian wife going slowly out of her mind in exile, the vain old peasant who's conned into a drug ambush, and Ollie's horrid mom, an indelible portrait of self-delusion, foolish loyalty, and venom. The last 40 or 50 pages of Single & Single seem hurried, barely skirting the implausible as the manhunt comes to a close in a remote stone farmhouse. And frankly, the end itself is a big letdown — too noisy, too much firepower, too obviously John le Carre's concession to commerce. You can tell that his heart just isn't in staging gunfights and commando raids. No matter. His heart is in everything else here. There aren't very many writers who can ratchet up the tension, notch by painful notch, and then just as deftly defuse it — by having the hero make squeaky balloon animals. A-