Hämäläinen (history, St. Catherine’s Coll., Oxford Univ.; Comanche Empire) is one of the world’s leading experts on nomadic equestrian peoples. His latest monograph focuses on the evolution of the Lakota from the 16th to 21st century. They initially were ensconced in the Missouri Valley where they proved influential in opposing the imperial designs of England, France, and Spain. In rising up against the colonial powers, they laid the foundation for later dominance of the Missouri Valley by the United States. By that time, the Lakota had adopted an equestrian lifestyle and had come to dominate the Great Plains. Their prowess as horsemen was evident at the Battle of the Little Big Horn, where they delivered a devastating victory to George Armstrong Custer and the Seventh Cavalry. Although a great victory, the Lakota lost the Great Sioux War of 1876–77 since they could not match the sheer numbers of the soldiers utilized by the United States during the conflict. The ability to adapt to changing circumstance, as exhibited first in the Missouri Valley and later in the Great Plains, has continued into the present, as the Lakota have been central to the effort to demand tribal sovereignty. VERDICT An essential purchase for all collections of American history and Native American studies.