While faulting the novel for "extreme unevenness", "Galaxy" reviewer Floyd C. Gale concluded that "A Case of Conscience" was "a provocative, serious, commendable work" and characterized it as "trailblazGalaxy's 5 Star Shelf", "Galaxy Magazine", February 1959, pp. 139–140.</ref> Anthony Boucher found Blish's protagonist "a credible and moving figure" and praised the opening segment; however he faulted the later material for "losfocus and impact" and "wander[ing" to an ending that seems "merely chaotic." In his "Books" column for "The Magazine of Fantasy & Science Fiction", Damon Knight selected Blish's novel as one of the ten best science fiction books of the 1950s. He reviewed the novel as "resonat with a note of its own. . . . it is complete and perfect."