by Harry Mulisch.Viking, $19.95. Mr. Mulisch’s novel centers on an elderly, third-rate (or worse) theatrical performer who is dragged out of retirement to play the lead in a melodrama about an elderly actor playing Prospero while contending with the offstage machinations of the supporting cast. The producer and director of the affair are addlepated idealists, and the author has to be quite mad—how otherwise could he hope to get away, even in Dutch, with incorporating large chunks of Shakespeare into his own versifications? The situation, however, enables Mr. Mulisch to engage in elaborate meditations on the relation of art to life, of imagination to reality, of theatrical contrivance to spontaneous action. The writing is so good and the rehearsal scenes so convincing that the reader is led to expect far more than this ultimately disappointing novel delivers.