For three decades following the expedition with Meriwether Lewis for which he is best known, William Clark forged a meritorious public career that contributed even more to the opening of the West: from 1807 to 1838 he served as the U.S. government’s most important representative to western Indians. This biography focuses on Clark’s tenure as Indian agent, territorial governor, and Superintendent of Indian Affairs at St. Louis. Jay H. Buckley shows that Clark had immense influence on Indian-white relations in the trans-Mississippi region specifically and on federal Indian policy generally. As an agent of American expansion, Clark actively promoted the government factory system and the St. Louis fur trade and favored trade and friendship over military conflict. Clark was responsible for one-tenth of all Indian treaties ratified by the U.S. Senate. His first treaty in 1808 began Indian removal from what became Missouri Territory. His last treaty in 1836 completed the process, divesting Indians of the northwestern corner of Missouri. Although he sympathized with the Indians’ fate and felt compassion for Native peoples, Clark was ultimately responsible for dispossessing more Indians than perhaps any other American. Drawing on treaty documents and Clark’s voluminous papers, Buckley analyzes apparent contradictions in Clark’s relationship with Indians, fellow bureaucrats, and frontier entrepreneurs. He examines the choices Clark and his contemporaries made in formulating and implementing Indian policies and explores how Clark’s paternalism as a slaveholder influenced his approach to dealing with Indians. Buckley also reveals the ambiguities and cross-purposes of Clark’s policy making and his responses to such hostilities as the Black Hawk War. William Clark: Indian Diplomat is the complex story of a sometimes sentimental, yet always pragmatic, imperialist. Buckley gives us a flawed but human hero who, in the realm of Indian affairs, had few equals among American diplomats.