I only read non-fiction; mostly philosophy. Here are some books off the top of my head: * The Inner Citadel/Philosophy as a Way of Life by Pierre Hadot * Plato's dialogues (someone already mentioned a few of them, but the Republic was missing from their list). * Epictetus (Discourses and Enchiridion) * The various essays/letters of Seneca * Matter and Consciousness by Churchland (older, but fascinating) * The Mediations of Marcus Aurelius * (mostly) any Buddhist texts * What a Plant Knows * Moonwalking with Einstein There are tons of fascinating books, way too many to list.
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