Everything you need to understand or teach A Case of Conscience by James Blish.
The social concerns, which are central to dozens, perhaps hundreds of science fiction works of the period, are actually secondary to Blish's main purpose in A Case of Conscience. Their role is merely to provide supporting evidence. What Blish is really interested in, and this was to become the theme of much of his major fiction in the years to come, was the problem of evil and, more specifically, the relationship between evil...