FOR Nabokov writing for the stage was like playing chess without his queen. In fiction his prose could thrive on capturing the unpredictables of the moment (a chance visual impression, a whim of private thought) and at the same time transcending the moment by the sheer force of style. In drama he can achieve neither effect. No wonder his moves on the chessboard of the stage seem so much weaker than his normal game. But Nabokov relished the challenge, and sought other modes of attack: a breakneck speed, a sense of headlong direction quite alien to his novels.