After Such Knowledge
(trilogy by James Blish)

1.  A Case of Conscience (1959)
2.  Doctor Mirabilis (1964)
3a. Black Easter (more correctly titled Black Easter, or Faust Aleph-null) (serialized as Faust aleph-null in If magazine, 1967)
3b. The Day After Judgment (1971)

Blish declared this group of novels to be a trilogy, each dealing with an aspect of the price of knowledge, and given the overall name of After Such Knowledge (the title taken from a T. S. Eliot quote). The first published, A Case of Conscience (a winner of the 1959 Hugo Award as well as 2004/1953 Retrospective Hugo Award for Best Novella), showed a Jesuit priest confronted with an alien intelligent race, apparently unfallen, which he eventually concludes must be a Satanic fabrication. The second, Doctor Mirabilis, is a historical novel about the medieval proto-scientist Roger Bacon. The third, actually two very short novels, Black Easter and The Day After Judgment, was written using the assumption that the ritual magic for summoning demons as described in grimoires actually worked. In that book, a powerful industrialist and arms merchant arranges to call up demons in the midst of a modern world crisis, resulting in nuclear war and the destruction of civilization. Black Easter is devoted to that element of the plot; The Day After Judgment is devoted to exploring the consequences of the destruction of the world, with an extraordinary ending in both narrative and theological terms that should not be given away.