"The Screwtape Letters," CS Lewis's epistolary novel about demons trying to win souls (which they intend to eat). Heck is depicted as a sprawling and backstabby bureaucracy, and the "voice" of Screwtape is eminently entertaining. Since the book is short and rereadable, I can come back to it every few years and find something new. For example, this time I discovered Lewis btfo'd dramatard !christians before we even existed.

[The demons' quarry] can be made to take positive pleasure in the perception that the two sides of his life are inconsistent. This is done by exploiting his vanity. He can be taught to enjoy kneeling beside the grocer on Sunday just because he remembers that the grocer could not possibly understand the urbane and mocking world which he inhabited on Saturday evening; and contrariwise, to enjoy the bawdy and blasphemy over the coffee with these admirable friends all the more because he is aware of a "deeper" "spiritual" world within him which they cannot understand. You see the idea--the worldly friends touch him on one side and the grocer on the other, and he is the complete, balanced complex man who sees round them all. Thus, while being permanently treacherous to two sets of people, he will feel, instead of shame, a continual undercurrent of self-satisfaction.