Unsong is a book about evil. Like HPMOR, it deals with places of unlimited suffering. It also combines Jewish Mysticism with Bay Area Tech culture.
The opposite of love is not hate, but indifference?
Acher and eating meat The story of Acher - why are some evil things acceptable and some non-evil things unacceptable? Or more relevant to today, why are some evil things completely acceptable, when some similarly evil things are completely unacceptable?
The book of Job