One of the enigmas of contemporary fiction, Walter Michael Miller, Jr., lives in carefully guarded privacy, an author/recluse as intriguing as J.D. Salinger or Thomas Pynchon. But no author refines himself entirely out of existence. His work must reveal something of him, and in Miller's the reader discovers a man who espouses a complex view of man's destiny and the human condition. Although he sees man as a fallen being, Miller's education and temperament preclude his resisting the temptation to glorify man's achievements and cosmic potential, and in story after story he presents a vision of man's dissemination through the solar system and into the galaxy. Thus while Miller characteristically qualifies his celebrations of the human spirit with frequent auguries of fearsome developments in evolution and disastrous nuclear wars, he also hints, in works like "Dark Benediction" (1951), "Conditionally Human" (1952; both collected in Conditionally Human, 1962),and A...