Clayton K. S. Chun 
US Army in the Plains Indian Wars 1865 1891 [PDF ebook] 

The Plains Indian War was one of the most controversial conflicts in American military history, as the US Army faced a tough opponent that challenged it for decades following the end of the Civil War. The Army leadership endured a severe lack of resources, political constraints, an indifferent public, tough environmental conditions, and other problems of the frontier. Army officers and men had to adapt to these constraints, and this period also proved to be a trial of the ability and endurance of the common soldier. This title details the organization, development, training, tactics and command structures of the US Army during its subjugation of the Plains Indian tribes.