Rationalism

Meditations of Marcus Aurelius

The Method, Meditations and Philosophy of Descartes

The Jefferson Bible

Six Metaphysical Meditations

Rules for the Direction of the Mind

Delphi Collected Works of Baruch Spinoza (Illustrated)

The Critique of Practical Reason

Meditations on First Philosophy & Other Metaphysical Writings

The Culmination

Arrows of Freethought

Essays Upon Some Controverted Questions

Essays in Rationalism

From Rome to Rationalismor: Why I Left the Church

Letters to Eugenia; Or, A Preservative Against Religious Prejudices

Leibniz's New Essays Concerning the Human Understanding: A Critical Exposition

On the Improvement of the Understanding

A Plea for Atheism

A Grammar of Freethought

Why I Do Not Believe in God

Lectures of Col. R. G. Ingersoll – Latest