Ficciones — Jorge Luis Borges (1944)

Jorge Luis Borges's Ficciones consists of 17 stories that are also philosophical essays, mathematical thought experiments, and metaphysical puzzles — each one exploring a single idea (an infinite library, a man with perfect memory, a map that exactly matches the territory it represents) with the precision of a proof and the strangeness of a dream. They invented postmodern fiction decades before the term existed and influenced virtually every serious writer of the late 20th century.