In this fourth volume of Ingersoll's works, the reader comes across one of the political activist's best-known lectures, "Why I Am an Agnostic;" also "The Truth," in which Ingersoll calls the science of theology the only dishonest science; "How to Reform Mankind;" "Thanksgiving Sermon;" "A Lay Sermon;" "The Foundations of Faith;" "Superstition;" "The Devil;" "Progress;" and "What Is Religion?"