A Case of Conscience

A very unique book. Blish is using the science fiction medium to examine religion and faith in a modern society. Satan is only supposed to have the power of illusion, not creativity (unlike God), but we have the existence of a planet whose inhabitants have no religion and no evil, either -- a place not completely unlike what Eden would have been before the fall. The planet of Lithia is therefore looked upon as a heresy by the protagonist, Ruiz-Sanchez (a Jesuit-scientist), whose scientific mind is at odds with his religion.

The ending is satisfying for me because it can be looked at from either a faithful (religious) or scientific point of view. The novel is short and there is very poor characterization and world-building, but the theological ideas are enough to recommend it alone.