In almost any spy story there comes a moment when a reader with his eyes open is forced to say to himself "this whole plot is downright ridiculous." No matter how skillful the author, unless he is that rare Graham Greene with the ability to tell stories about spies instead of spy stories, he inevitably introduces the jarring, discordant note which drives the whole plot beyond the limits of believability.

A wave of recent spy novels attempted to combat this inevitable moment by conceding defeat--by making the story so essentially ridiculous that the reader begins and ends in disbelief.

The Spy Who Came in from the Cold, John Le Carre's second novel, takes the opposite tack. Its people are so down-to-earth that the adventure story fades into the background. As a thriller, the book is slightly better than average -- not extraordinary. There is an unusually complicated plot, but one that can be seen through without undue exertion. There is the usual cast--a secret agent, Alec Lemas, assorted other agents, a chief-of-department named "Control," and a girl whom Lemas loves, and who happens to be a Communist.

But it's here that the twists take place--these stock characters have taken on new characteristics. Control is no ruthlessly efficient genius, but a pompous, vain bureaucrat who "always likes to be in on a good thing." Lemas has his bureaucratic side too, and he too is proud, often petty, knowing that he is working for a ruthless machine, but unwilling to stop.

Perhaps the best-drawn character of all is Liz Gold, Lemas' girl. A party member, she isn't a dedicated Communist or a dedicated anything-else. She joined the party because she thought its ideals were beautiful, although she disliked standing on street corner selling the Worker. She is devoted to Lemas and her idealism is the perfect counterpoint for his realism. To her, a secret service agent he must kill is a man, better than many of Lemas' own associates. To him, he is an enemy to be killed, and killing is a job that must be done.

Le Carre's ability to etch characters and his fine hand with dialogue are characteristics of a good novelist, not merely of a writer of good spy stories. It would be a pity if he settled down to become a hack adventure writer after his success with this book