For more than half a century, the Japanese Ministry of Foreign Affairs (Gaimushō) possessed an independent police force that operated within Japan's informal empire on the Asian continent. Charged with “protecting and controlling” local Japanese communities first in Korea and later in China, these consular police played a critical role in facilitating Japanese imperial expansion during the late nineteenth and twentieth centuries. This book describes how the Gaimushō police became deeply involved in the surveillance and suppression of the Korean independence movement in exile throughout Chinese treaty ports and the Manchurian frontier during the 1920s and 1930s. It had in fact evolved over the years from a relatively benign public security organization into a full-fledged political intelligence apparatus devoted to apprehending purveyors of “dangerous thought” throughout the empire. While historians often still depict the Gaimushō as an inhibitor of unilateral military expansionism during the first half of the twentieth century, the book's exposé on the activities and ideology of the consular police dramatically challenges this narrative. Revealing a far greater complexity of motivation behind the Japanese colonial mission, it illustrates how the imperial Japanese state viewed political security at home as inextricably connected to political security abroad from as early as 1919—nearly a decade before overt military aggression began—and approaches northeast Asia as a region of intricate and dynamic social, economic, and political forces.