A Case of Conscience

A Case of Conscience is a science fiction novel by American writer James Blish, first published in 1958. It is the story of a Jesuit who investigates an alien race that has no religion yet has a perfect, innate sense of morality, a situation which conflicts with Catholic teaching. The story was originally published as a novella in 1953, and later extended to novel-length, of which the first part is the original novella. The novel is the third part of Blish's thematic After Such Knowledge trilogy: it thus follows Doctor Mirabilis and Black Easter and The Day After Judgment (two short novels that Blish viewed as forming the second volume of the trilogy).