Colonel Rogers' study of the equipment, organization and method of fighting of the Civil War armies has been unavailable for some years. Colonel Rogers not only drew upon his experience as a decorated British Army officer to take a fresh look at the structure of the Northern and Southern armies and select representative actions, but he made often surprising use of eyewitness accounts by European observers of Civil War organization, unit capabilities and actions.

Rogers examines in detail each branch of the armies, not only infantry, cavalry and artillery, but engineers, signals, railways, supply, medical, staff, and naval support. Emphasis is placed on the state of these units at the outbreak of war and how this influenced their later operations. Chancellorsville is selected as the major example of the units in action, but novel use is made of other engagements, some of them neglected in recent years.

American writers have somewhat downplayed the large number of European military professionals who traveled with or observed the Civil War armies, but Rogers makes good use of the descriptions left by Garnet Wolseley, Arthur Fremantle, the Comte de Paris, the Duc de Chartres, and war artist Frank Vizetelly in what is still a fresh and perceptive analysis.