The Essential Works of Robert G. Ingersoll in twelve volumes comprises philosophical, political religious, and other literary works by American writer and orator.

Table of Contents:
Volume 1:
The Gods
Humboldt
Thomas Paine
Individuality
Heretics and Heresies
The Ghost
The Liberty of Man, Woman, and Child
Conclusion
About Farming in Illinois
What Must We do to be Saved?

Volume 2:
Some Mistakes of Moses
Some Reasons Why
Orthodoxy
Myth and Miracle

Volume 3:
Shakespeare
Robert Burns
Abraham Lincoln
Voltaire
Liberty in Literature
The Great Infidels
Which Way?
About the Holy Bible

Volume 4:
Why I am an Agnostic
The Truth
How to Reform Mankind
A Thanksgiving Sermon
A Lay Sermon
The Foundations of Faith
Superstition
The Devil
Progress
What is Religion?

Volume 5:
Ingersoll's Interviews on Talmage
The Talmagian Catechism
A Vindication of Thomas Pain
The Observer's Second Attack
Ingersoll's Second Reply

Volume 6:
The Christian Religion
Faith or Agnosticism
The Field-Ingersoll Discussion
A Reply to the Rev. Henry M. Field
A Last Word to Robert G. Ingersoll
Letter to Dr. Field
Controversy on Christianity
Col. Ingersoll to Mr. Gladston
Rome or Reason
The Church Its Own Witness
Is Divorce Wrong?
Divorce
Is Corporal Punishment Degrading?

Volume 7:
My Reviewers Reviewed
My Chicago Bible Class
To the Indianapolis Clergy
The Brooklyn Divines
The Limitations of Toleration
A Christmas Sermon
Suicide of Judge Normile
Is Suicide a Sin?
Is Avarice Triumphant?
Replies and Interviews

Volume 8:
The Bible and a Future Life
Mrs. Van Cott, The Revivalist
European Trip and Greenback Question
The Pre-Millennial Conference
The Solid South and Resumption
The Sunday Laws of Pitsburg
Political and Religious…

Volume 9:
Speeches and Addresses

Volume 10:
Address to the Jury in Various Cases

Volume 11:
Address on the Civil Right Act
Trial of C. B. Reynolds for Blasphemy
God in the Constitution
A Reply to Bishop Spalding
Crimes Against Criminals
A Wooden God
Some Interrogation Points
Art and Morality
The Divided Household of Faith
Huxley and Agnosticism…

Volume 12:
Prefaces, Tributes, and Essays