The Sheep Industry of Territorial New Mexico offers a detailed account of the New Mexico sheep industry during the territorial period (1846–1912) when it flourished. As a mainstay of the New Mexico economy, this industry was essential to the integration of New Mexico (and the Southwest more broadly) into the national economy of the expanding United States. Author Jon Wallace tells the story of evolving living conditions as the sheep industry came to encompass innumerable families of modest means. The transformation improved many New Mexicans’ lives and helped establish the territory as a productive part of the United States. There was a cost, however, with widespread ecological changes to the lands—brought about in large part by heavy grazing. Following the US annexation of New Mexico, new markets for mutton and wool opened. Well-connected, well-financed Anglo merchants and growers who had recently arrived in the territory took advantage of the new opportunity and joined their Hispanic counterparts in entering the sheep industry. The Sheep Industry of Territorial New Mexico situates this socially imbued economic story within the larger context of the environmental consequences of open-range grazing while examining the relationships among Hispanic, Anglo, and Indigenous people in the region. Historians, students, general readers, and specialists interested in the history of agriculture, labor, capitalism, and the US Southwest will find Wallace’s analysis useful and engaging.