The Great Agnostic: Robert Ingersoll and American Freethought.
New Haven, Connecticut: Yale University Press, 2013.
Book information: Publisher; Google Books; Amazon.com.
Links:
- Susan Jacoby, her promotional website.
 - Susan Jacoby, Wikipedia.
 - Robert G. Ingersoll (1833–1899), Wikipedia.
 
Selected Works of Ingersoll:
- Abraham Lincoln, A Lecture.
 - Shakespeare, A Lecture.
 - Voltaire, A Lecture.
 - Testimonial to Walt Whitman.
 - The Great Infidels, A Lecture.
 
The Works of Robert G. Ingersoll:
- Volume 1, Lectures.
 - Volume 2, Lectures.
 - Volume 3, Lectures.
 - Volume 4, Lectures.
 - Volume 5, Discussions.
 - Volume 6, Discussions.
 - Volume 7, Discussions.
 - Volume 8, Interviews.
 - Volume 9, Political.
 - Volume 10, Legal.
 - Volume 11, Miscellany.
 - Volume 12, Tributes and Miscellany.
 - Volume 12, Miscellany.
 - Volume 13, A Biographical Appreciation by Herman E. Kittredge.