When Dick Helms became CIA Director in mid-1966, he ordered Saigon Station to penetrate the North Vietnamese and Vietcong (VC) intelligence services. When years passed with little progress, he called in Mr. Locke, an old friend and a senior counterintelligence officer. "Charlie, I'm frustrated. We know a lot about VC capabilities, but not nearly enough about their intentions. And we won't know those until we penetrate them. Saigon Station's too damned...