<p> Between 1889 and 1914, American mining engineers drew on their experience in mining in the American West into management positions with prominent mining finance firms in the British Empire. The careers of three engineers, Hennen Jennings, John Hays Hammond, and Herbert Hoover, demonstrate their influence on British gold mining investment and on the imperial system. The professional biographies of these engineers demonstrate their racialized labor practices, access to technology and capital, ideas about management, and willingness to interfere in the politics and economies of sovereign nations for the interests of the mining finance industry, notably the Transvaal Republic and late Qing China. In their actions in the colonies, they employed the latest mining technologies to extract gold from low grade ores, imposed labor conditions on the basis of race (including the legal foundations of Apartheid in South Africa), and directed investment capital toward profitable mining in support of the monetary gold standard and shareholder dividends. Along with hundreds of other mining engineers, they oversaw a world-historical expansion of the world&rsquo;s gold supply through the expansion of gold mining on the Witwatersrand in the Transvaal Republic and in Western Australia, effectively doubling the world&rsquo;s supply of gold in two decades. </p><p> These engineers were agents of transnational extractive capitalism and the British and American empires. As an integral component of their careers, they operated in the core of empire: major centers of investment such as London and New York, the media and publishing worlds, and even world&rsquo;s fairs. They communicated their professional activities and technical developments through the <i>Engineering and Mining Journal,</i> the premier mining publication of the era. They promoted world&rsquo;s fairs, ensuring that mining was prominently featured as an aspect of civilization at these expositions. They also acted as public intellectuals, speaking and publishing on topics of empire, well beyond the purview of the mine. Based on archival research, contemporary technical journals and media accounts, and autobiographical documents, this dissertation analyzes the influence of American Mining Engineers, both good and bad, in shaping the British Empire and the modern world system before the outbreak of World War 1.</p><p>