Tinker, Tailor, Soldier, Spy, by John le Carre. New York: Bantam Books Inc.

British Intelligence needs former spy George Smiley's help once more. A top British agent has defected. In spy jargon he has become a "mole," cared for and nourished by the Soviets.

Smiley burrows in and delves as deviously as the mole, and it is not until the final pages that we discover which of the five suspects the Kilby-like traitor really is.