Drawing on recently declassified intelligence files, Lauren Young details how sympathy for the Nazi cause pervaded the British aristocracy, with significant factions of the upper class actively and methodically pursuing a pro-German agenda. Young exposes the involvement of secret organizations such as the Right Club, which counted the Duke of Wellington among its influential members;the Cliveden Set, which ran a shadow foreign policy supporting Hitler;and the shocking relationship between the socialite Unity Mitford and Adolf Hitler. Eye-opening and instructive, this book reevaluates 1930s England to help us understand our vulnerabilities today, including the Russian oligarchy and the invasion of Ukraine, Brexit, and the election of Donald Trump.