Books in Philosophy (sorted alphabetically)
- System of Logic: Ratiocinative and Inductive, 7th Edition, Vol. II John Stuart Mill
- System of Logic, Ratiocinative and Inductive (Vol. 1 of 2) John Stuart Mill
- Theaetetus Plato
- Theological-Political Treatise [Part III] Benedictus de Spinoza
- Theological-Political Treatise [Part IV] Benedictus de Spinoza
- Theological Tractates and The Consolation of Philosophy (Latin) Boethius
- Theologico-Political Treatise — Part 1 Benedictus de Spinoza
- Theologico-Political Treatise — Part 2 Benedictus de Spinoza
- Three Dialogues Between Hylas and Philonous in Opposition to Sceptics and Atheists George Berkeley
- Thus Spake Zarathustra: A Book for All and None Friedrich Wilhelm Nietzsche
- Tractatus Logico-Philosophicus (German) Ludwig Wittgenstein
- Treatise Concerning the Principles of Human Knowledge George Berkeley
- Treatise of Human Nature David Hume
- Utilitarianism John Stuart Mill