[Harold Pinter, the] obscure, difficult playwright of the early '60s has emerged, two decades later, as our foremost exponent of naturalism. Pinter, we are told, has changed. Hardly: Pinter's style and themes have remained remarkably intact. He is now, as he has almost always been, primarily concerned with power relationships between men, with the ambiguous tension of sexuality, with the unspoken difficulties of an unacknowledged class system. But Pinter does write mystery plays, in both the secular and the religious sense of the word: He takes us on a search for the unknown during which he manages to physicalize the unknowable. Secrets do not give themselves up in Pinter's work; we learn about the nature of secrets instead.

On the surface of things, no play should seem less secretive than Betrayal. The work is more or less constructed backwards …; the path of discovery is to see how...