In the late nineteenth century, the Texas Rangers and Canada's North-West Mounted Police were formed to bring the resource-rich hinterlands at either end of the Great Plains under governmental control. Native and rural peoples often found themselves squarely in the path of this westward expansion and the law enforcement agents that led the way. Though separated by nearly two thousand miles, the Rangers and Mounties performed nearly identical functions, including subjugating Indigenous groups; dispossessing peoples of mixed ancestry; defending the property of big cattlemen; and policing industrial disputes. Yet the means by which the two forces achieved these ends sharply diverged; while the Rangers often relied on violence, the Mounties usually exercised restraint, a fact that highlights some of the fundamental differences between the U.S. and Canadian Wests. Policing the Great Plains presents the first comparative history of the two most famous constabularies in the world. Andrew R. Graybill is an assistant professor of history at Southern Methodist University in Dallas, TX.