The Plains Indian War was one of the most controversial conflicts in American military history. Army commanders schooled in jominian strategy and experienced with the mass and maneuver tactics of the American Civil War were thrown into a tough situation. In this title, Dr Chun examines the organization and evolution of the US Army through highly detailed orders of battle, TOEs and examinations of crucial aspects such as command structure, doctrine, training, tactics and combat missions. The Departments of Dakota, the Platte, and the Missouri are examined, including Custer's defeat at the Little Bighom.