Though the scholarship on the Civil War is vast, Changing Sides represents the first entry to investigate Union POWs who fought for the Confederacy, filling a significant gap in the historiography of Civil War incarceration. To provide context, Patrick Garrow traces the history of the practice of recruiting troops from enemy POWs.

"Garrow's book investigates the experience of imprisoned Union soldiers during the final years of the American Civil War, including their captivity and their repatriation into Confederate ranks. Patrick Garrow's research stems from the archaeological excavation of Florence Prison in 2006 and subsequent archival research in the Official Records of the War of the Rebellion and other primary records. Garrow's deeply researched portrait will fill a significant gap in our understanding of Union POWs, since Dee Brown's lengthy work, Galvanized Yankees, dating back to the 1960s, largely focused on Confederate POWs that fought for the Union"--