James Blish: Black Easter
While primarily known for sci-fi stories, including various Star Trek stories, James Blish also wrote one of the greatest works of occult fiction: Black Easter. From what I have read, Blish developed the idea for Black Easter by deciding to write something where magic is definitely real and works just as it is supposed to, but using only magical tomes that really exist, rather than any invented ones, such as The Necronomicon . Paperback edition by Dell The story is quite simple, but also rather fascinating. It revolves around a practitioner of magic, Theron Ware, who performs various rituals for hire. He is approached by an arms dealer who wants to try something of an experiment. After Ware performs some smaller feats for him, convincing him of the efficacy of magic, the arms dealer says he wants to free all the demons of hell for one night. Ware finds that he is actually quite interested in this idea, so he agrees. The bulk of the story deals with Ware p...