James Blish’s Hugo Award-winning masterpiece is a foundational work of theological science fiction that remains as provocative today as it was in 1958. Through the eyes of Jesuit biologist Father Ruiz-Sanchez, Blish explores the collision of faith, cold logic, and alien evolution on the planet Lithia. This Del Rey edition is an essential addition for any collector of mid-century speculative fiction interested in the philosophical depth of the Golden Age.