The author of this technical study is an archeologist with experience in Yemen, and a leading specialist on Global Positioning System and Geographic Information Systems mapping. He uses those tools to compare the water histories of two arid regions, Southwest Arabia, c. 3500 BCE–600 CE, and the American West, c. 2000 BCE–1950 CE. He analyzes how the two areas—far removed from each other in time, culture and history—“are unique in similar ways,” emphasizing environmental, social, political and religious factors. This leads him into discourses on xenophobia, Orientalism, water crises, Western water law and even the War on Terror. Surprisingly, he does not discuss a living link between Yemen and the American West: acequias, the gravity-flow irrigation ditches that evolved over 10,000 years in the deserts of the Middle East. Carried to Spain by the Moors and thence to the New World, including the American Southwest, acequia technology endures in northern New Mexico and southern Colorado.