Why Spy?

By Martha Duffy

THE INNOCENT by Ian McEwan

Doubleday; 271 pages; $18.95

For the past several months, readers and publishers have been mourning the end of the cold war. Fine for the future of mankind, of course, but it means curtains for that sturdy subindustry, the espionage thriller. Goodbye to the Berlin Wall? A bitter thought. And what of double agents? No one still believes their entrapments occurring in the Middle East, where messages are not coded but exploded.

The Innocent may be remembered not only as deft, taut fiction, but also as the book that showed the way out of the quagmire of glasnost. Ian McEwan, a British novelist who is a breathtaking master of nasty fiction (The Cement Garden), as well as a few sentimental excursions (The Child in Time), has written a blueprint for the future of the genre. The key is not in nostalgia, evoking the bleak era when real men wore raincoats, but in the brisk assumption of a '90s vantage point, leaving the author free to make all kinds of moral and social comments -- rather like choreographing the doings at an ant farm.

McEwan's story is set in Berlin in 1955, when the cold war was in full swing. The innocent of the title is Leonard Marnham, 25, a British post-office technician who is drafted into an undercover operation in which the allies are cooperating. And undercover is the accurate word; they are digging a tunnel in the Russian sector to pick up Soviet signals. Leonard loves his work. After living a cramped life in Tottenham, he relishes the rooms "big as meadows" in his government-issue flat and the hip manners of his co-workers. He soon learns that "you did not speak to people unless their work was relevant to yours. The procedure evolved, partly . . . out of a concern for security and partly out of a certain virile cult of competence."

Leonard's chief adviser is a fine comic creation, an American named Glass, who sees a spy lurking on every barstool. On one pub crawl, they meet a pretty German divorcee named Maria, and she and Leonard begin an idyllic affair in which they make up their own rules of behavior. But one night, for reasons quite obscure to him, he acts sadistically, and their romance becomes more conventional.

How Leonard ends up with two cruelly heavy suitcases filled with human remains is the climax of The Innocent, told with all McEwan's frigid skill. The last part of the book is a hilarious account of the young man's attempts to rid himself of his obnoxious burden. The cases won't fit in railway lockers. A dog smells their contents and tries frantically to avenge the canine species for centuries of subjugation. Finally exhausted, Leonard draws the vultures of both security and treachery to the tunnel.

Many English writers have been compared to Evelyn Waugh, often wrongly, but this book can stand with the master's best, at least for its sheer, mirthful heartlessness. The author caps his tale with an insouciant coda that envisions his middle-age hero thinking of a return to the Wall, "before it was all torn down."