"I don't understand this mania for surprises," says a Russian scientist about spy novels in Tom Stoppard's Hapgood. "If the author knows, it's rude not to tell. In science, the ending is understood: What is interesting is to know what is happening."

But for playwright Stoppard, mystery is precisely the point of Hapgood -- a foray into the strange world of espionage, filled with deceit, trickery, and game-playing. Intelligence work, in Stoppard's view, is like quantum physics: an enigma. What you see isn't necessarily what you get. According to modern physics, light can appear as either a particle or a wave, depending upon how you look at it. And the very act of obse[...]