After decades of optimism, elites in the United States, Australia, and the United Kingdom have reframed the People's Republic of China as a long-term competitor.The Dragon Defined: How Washington, Canberra, and London Reimagined China explains this shift as a hegemonic field effect: an emergent political and ideological alignment shaped by American global influence since 2016. From this perspective, the United States, Australian, and United Kingdom's responses to China's rise are at once country-specific-China looks very different from Washington, Canberra, and London-yet reflect the contemporary dynamics of American hegemony, where political priorities and modes of knowing friends, rivals, and enemies are exported to those in its hegemonic orbit. In Washington, a vibrant and expanding think tank space, coupled with an open door to government, creates an intense struggle over the framing of issues like China, reflected in a sharp turnover from Engagement to Strategic Competition after the election of Donald Trump. The smaller Australian and UK security fields display unique changes in China strategy, yet they have increasingly aligned with the US on China's rise. As canaries in the coalmine" of East Asia, Australia's leaders have had an outsized effect on US strategic thinking. Drawing on over 250 original interviews with former diplomats, strategists, and academics across the three countries--and melding constructivist approaches to International Relations with the sociology of expertise--The Dragon Defined: How Washington, Canberra, and London Reimagined China offers a theoretically innovative and thickly descriptive account of the politics of China knowledge in Washington, Canberra, and London.