The best philosophy books are subjective and vary depending on the reader's interests and the particular subfield of philosophy they choose to study. Nonetheless, the following well-known and respected philosophical works have made a big difference in the field Philosophy Books Description Marcus Aurelius' Meditations A collection of the Roman Emperor's private letters that provide insights into practical wisdom and Stoic philosophy. Plato's Republic A seminal treatise examining justice, the soul's nature, and the perfect condition. Aristotle's Nicomachean Ethics Aristotle's investigation of morality, virtue, and living a decent life. Immanuel Kant's Critique of Pure Reason A foundational work in contemporary philosophy that explores epistemology and metaphysics.