In recent years, scholars of religion have separately fastened on missionaries and intelligence services as promising subjects of study. Matthew Avery Sutton fuses the two in this lively account of Christianity's role in the wartime creation of the US Office of Strategic Services (OSS). Missionaries, he notes, were ‘masters at infiltrating other cultures in order to transform them from the inside out’ (p. 28), a skillset of infinite worth for a nation with a modest foreign service but growing international ambitions. William Donavan, founder of the OSS, and Allen Dulles, inaugural civilian director of the CIA, recruited ‘dozens’ of missionaries to aid this work, sometimes hiring those already in the field while occasionally fabricating missionary cover for new agents (p. 96). Depending on the locale, this could include women (p. 98), but most of the recruits were men, and Sutton builds his narrative around four key figures: the Episcopalian educator William Eddy, the fundamentalist missionary John Birch, the ecumenical administrator Stephen Penrose and the Lutheran minister Stewart Herman Jr. While other operatives and religious traditions – such as the Belgian Catholic priest Fr. Felix Morlion and the American rabbi and archaeologist Nelson Glueck – appear from time to time, the experiences of these four Protestants inform most of Sutton's conclusions. Always rich, the four portraits are not as consistently generous. Birch's faults receive less mitigation than do those of the three mainline Protestants, and only in the closing chapter do readers encounter the intriguing hypothetical that fundamentalism's suspicion of concentrated power might have checked eventual CIA overreach more effectively than did the theology of Eddy and Penrose (p. 331). The book is pitched more towards the general reader than the specialist. Experts in mid-century Protestantism, for example, might crave a slight expansion of Sutton's assessment of the significance of Niebuhrian realism on these pious spooks (pp. 35–6, 98). Despite repeated allusions to the seeming contradiction between these men's Christian faith and their willingness to engage in (or at least plot) violence (for example, p. 189), the text likewise foregoes analysis of how centuries of just war theory may have informed their actions; the demands of readability preclude such an excursus. Still, scholars owe Sutton substantial gratitude for his archival work, especially impressive given the project's content: secretive by design, intelligence leaders worried that any avowal of missionary involvement would cast suspicion upon all Christian emissaries and adjusted the documentary record accordingly (pp. 105, 320–1). With relentless detective work spread across fifteen-plus archives and numerous personal collections, Sutton has reconstructed a story that will prompt new questions and curiosities among specialists while gripping the attention of popular audiences.