Immortal Captives is two books in one. Mauriel Joslyn has used the story of 600 Confederate prisoners of war to provide insight into the larger questions about prisoner of war issues in the Civil War. Combining original scholarship with full quotations from the participants in the events she describes, she has created both a memorial to the captured officers who came to be held at Fort Pulaski, Georgia and a good history.

The policies of President Abraham Lincoln, Lieutenant General Ulysses S. Grant, in addition to those of lower ranking Union leaders come under reevaluation in this story. The Union deliberately chose 600 Confederate officers from fourteen Southern states for its policy of retaliation. Against humanity, those officers were forced to face the artillery fire of their comrades when they were placed in a stockade in Charleston Harbor from August to October of 1864.

Their ordeal continued when they were moved to Fort Pulaski for the winter. The last of them were not released until July 1865, months after the war ended.