- Ancient and Modern Celebrated Freethinkers
- Crito
- An Enquiry Concerning Human Understanding
- Phaedo
- The Ego and His Own
- The Ruins, or, Meditation on the Revolutions of Empires and the Law of Nature
- The Faith of Our Fathers
- The Metaphysical Elements of Ethics
- The Critique of Pure Reason
- Apology, Crito, and Phaedo of Socrates
- Statesman
- Discours de la méthode
- A Philosophical Dictionary, Volume 1
- On Being Human
- A Essay Towards a New Theory of Vision
- Ion
- Ethics — Part 3
- The Philosophy of Evolution
- Ethics — Part 1
- Timaeus
- Essays
- The Consolation of Philosophy
- Apology
- The Memorable Thoughts of Socrates
- The Investment of Influence
- Democracy and Social Ethics
- Initiation into Philosophy
- The Map of Life
- A Lie Never Justifiable
- Homer and Classical Philology
- How to Observe
- Plato and Platonism
- A Philosophical Dictionary, Volume 10
- How To Behave: A Pocket Manual of Republican Etiquette, and Guide to Correct Personal Habits
- How To Behave: A Pocket Manual of Republican Etiquette, and Guide to Correct Personal Habits
- Ethics — Part 5
- Liberalism
- Chinese Literature
- The Basis of Morality
- The Republic
- Littérature et Philosophie mêlées
- Politics: A Treatise on Government
- A Man's Value to Society
- L'homme Qui Rit
- The Critique of Practical Reason
- Ethics — Part 2
- The Philosophy of the Moral Feelings
- The Law and the Word
- Utilitarianism
- Thoughts out of Season Part I
- Our Fathers Have Told Us
- Levels of Living
- The Young Woman's Guide
- A Short History of Greek Philosophy
- Essays of Schopenhauer
- Civil Disobedience
- Atheism in Pagan Antiquity
- Book of Wise Sayings
- Moral Philosophy
- The Destiny of Man
- The Prince
- Essays Æsthetical
- Myth and Science
- Shorter Prose Pieces
- Eclectic School Readings: Stories from Life
- The Will to Believe : and Other Essays in Popular Philosophy
- The Physiology of Marriage, Part 2
- Ethics — Part 4
- The Unseen World and Other Essays
- Quotes and Images From The Confessions of J. J. Rousseau
- Laws
- The Ethics of Aristotle
- Essays
- The Existence of God
- Poetics. English
- The Selections from the Principles of Philosophy
- Beyond Good and Evil
- Thus Spake Zarathustra
- The Philosophy of Spinoza
- The Heart of the New Thought
- The Soul of Man under Socialism
- Feuerbach: The roots of the socialist philosophy
- Dialogues Concerning Natural Religion
- A Treatise of Human Nature
- Walden
- Sophist
- Notes from the Underground
- Varieties of Religious Experience, a Study in Human Nature
- Fundamental Principles of the Metaphysic of Morals
- The Philosophy of Despair
- Tragic Sense Of Life
- A Philosophical Dictionary, Volume 4
- Ainsi Parlait Zarathoustra
- Categoriae. English
- Improvement of the Understanding
- When a Man Comes to Himself
- Seekers after God
- A System of Logic: Ratiocinative and Inductive
- The Golden Sayings of Epictetus
- The Evolution of Man — Volume 1