Theism or Atheism: The Great Alternative

The Heavenly Father: Lectures on Modern Atheism

The Necessity of Atheism

The Basis of Early Christian Theism

Atheism Among the People

Humanity's Gain from Unbelief Reprinted from the "North American Review" of March, 1889

An Atheist Manifesto

Through Nature to God

Know the Truth: A Critique on the Hamiltonian Theory of Limitation Including Some Strictures Upon the Theories of Rev. Henry L. Mansel and Mr. Herbert Spencer

Christianity Unveiled Being an Examination of the Principles and Effects of the Christian Religion

Theism; being the Baird Lecture of 1876

Theism and Humanism Being the Gifford Lectures Delivered at the University of Glasgow, 1914