•Why it earns a slot
Why it earns a slot: it distills Schopenhauer's entire system into essays anyone can read in an afternoon, including the porcupine's dilemma, the single image later borrowed by Freud to describe human intimacy.
Schopenhauer argues pain is the real business of life and happiness is only its temporary absence, then follows that logic straight through suicide, women, and a huddle of porcupines.
This distillation is written from the freely available original, which is always the better read when you have the time: Project Gutenberg.