In Armies of Arabia—the first book to comprehensively analyze the Gulf monarchies’ militaries—Zoltan Barany explains the conspicuous ineffectiveness of these forces with a combination of political-structural and sociocultural factors. Based on over 150 personal interviews and meticulous multidisciplinary research, he offers a fascinating account of Arabia’s armies starting with Ibn Saud’s conquest of much of the peninsula and ending with the ongoing war in Yemen. He explores the ruling families’ role overseeing their militaries to ensure their loyalty and examines the backgrounds and career trajectories of soldiers and officers. Barany argues that Arabia’s armies remain ineffective because they are characterized by an absence of meritocracy, the domination of personal connections over institutional norms, disregard for personal responsibility, half-hearted leadership, casual work ethic, and training lacking intensity, frequency, and up-to-date settings. Massive expenditures on armaments are primarily payoffs to the United States for protecting them and have resulted in bloated arsenals and large-scale corruption. The setbacks of the Saudi-led coalition’s disastrous war in Yemen starkly illustrate the Gulf armies’ humiliating combat record. The book concludes with thoughts on waste (of human potential, resources, institutions) as a dominant theme of Gulf military affairs, considers likely changes in response to long-term weakening demand for oil, and suggests ways in which the effectiveness of Arabia’s armies could be raised. Chock-full of insights and stories from the field and written with a general audience in mind, Armies of Arabia is essential reading for anyone interested in military affairs and Middle Eastern politics, society, and international relations.