A college graduate at 16 and a founder of the Sigma Chi fraternity, Caldwell entered the Confederate Army as an artillery lieutenant. He fought at Shiloh, Port Hudson and other campaigns before being captured in 1863 and imprisoned on Johnson's Island, in Lake Erie, near Sandusky, Ohio. He kept a daily diary for 18 months, describing the prison food and conditions, as well as his classical and intellectual interests. The book features letters, a poem, notes, and an index.

Original t. p. reads: The adventures of a prisoner of war, and life and scenes in Federal prisons: Johnson's Island, Fort Delaware, and Point Lookout / by an escaped prisoner of Hood's Texas Brigade. Houston, Texas: Richardson & Owen's Printing Establishment, 1865.