Any info on this book? It's titled Digital Devil Story, and it was the basis for the original series.
From Harecore Gaming we know this about the book:
Megami Tensei began as a novel by Aya Nishitani. The story was about a young computer genius named Nakajima who had tapped into the world of demons through the use of computers - hence the subtitle "Digital Devil Story". Naturally, things go horribly wrong when he summons the evil fiend Loki into the real world, and it's up to Nakajima to right the wrongs he created. Namcot bought the video game rights and turned it into a role playing game for the Famicom.
I've been interested in the book ever since I read that but I can't find anymore info on it. Maybe I'm not looking hard enough? =/