Groundwork of the Metaphysics of Morals

Zero: The Biography of a Dangerous Idea

The Story Of Aristotle's Philosophy (Unabridged)

The Critique of Pure Reason, Volume 2

Summary of Will Durant & Ariel Durant's The Lessons of History

Kant's Foundations of Ethics

Philosophical Investigations

The World as Will and Idea: Volume 2

Kant: A Very Short Introduction

Foundations of Ethics

Schopenhauer: A Very Short Introduction

Dreams of a Spirit-Seer (Unabridged): optional

Philosophy 101: From Plato and Socrates to Ethics and Metaphysics, an Essential Primer on the History of Thought

Critique of Practical Reason

Philosophy of Science: A Very Short Introduction, 2nd Edition

The Critique of Practical Reason

The Philosophy Book: Big Ideas Simply Explained

Prolegomena to Any Future Metaphysics (Unabridged): optional

Human, All Too Human