Eleanor M. Gates’s End of the Affair: The Collapse of the Anglo-French Alliance, 1939-40 offers a meticulous diplomatic and military history that probes one of World War II’s most consequential ruptures: the breakdown of cooperation between Britain and France in the face of German aggression. Spanning from the uncertain early months of the war through France’s collapse in 1940, Gates reconstructs how strategic disagreements, mismatched military expectations, diplomatic misfires, and political pressure conspired to undermine the wartime alliance. She draws on previously unpublished documents, cabinet minutes, military plans, and diplomatic correspondence to examine: differences in war aims; conflicts over strategy (especially defense vs. offense); France’s internal political fragility; British hesitation; and the cumulative effects of distrust and unmet commitments. The narrative tracks moments like the Supreme War Council meetings, the French political debates over armistice versus resistance, and the fateful decisions about the French fleet and colonial positions. More than a recounting of foreign policy failure, End of the Affair illuminates how alliance politics, national character, and military capacity intertwine under stress. Gates argues that Britain and France entered the conflict with incompatible assumptions about how a modern war should be waged, and that each underestimated the internal challenges the other faced—France’s political divisions, fear of defeat, and Britain’s constraints in resources and resolve. The book underscores that the collapse of the alliance was not inevitable, but the result of avoidable miscalculations, communication breakdowns, and shifting domestic politics. For scholars of World War II, diplomatic history, and strategic studies, Gates’s work remains indispensable: it not only fills gaps in archival evidence, but also serves as a warning about how alliances may fracture even among formally committed partners. This title is part of UC Press's Voices Revived program, which commemorates University of California Press’s mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1981.