A Case of Conscience

A Case of Conscience is a science fiction novel by the American writer James Blish, first published in 1958 and expanded from a short novel that had appeared in If magazine five years earlier. The shorter version, which won a Retrospective Hugo Award in 2004, forms the first part of the book. Blish placed the novel at the head of a loose group of three works he called After Such Knowledge.

Father Ramon Ruiz-Sanchez is both a Jesuit and a working biologist, and he travels as one of a four-man scientific team sent to Lithia to establish whether the planet can be opened to human contact. He serves as the mission's doctor and its biologist, and he is the member who has taken the trouble to learn the Lithian language.

The Lithians are rational, courteous and generous, and entirely without greed, envy or cruelty. They have produced no literature, no fine art and no religion, and that last absence is the one Ruiz-Sanchez cannot set aside, because the conduct of these people matches the commandments he was taught to keep. He has to decide what a planet of virtuous unbelievers means, and then write it down for the people who sent him.