At the dawn of the twentieth century, the soybean was little more than a botanical curiosity beyond East Asia. Today, soy is planted on hundreds of millions of acres of farmland across multiple continents, it is a leading export of emerging and developed economies like those of Brazil and the United States, and is the third-most valuable crop in the world behind only rice and wheat. Yet throughout the historical spread of soybean cultivation, the value of soy was often far from self-evident, both to its potential consumers and to the farmers who came to grow the crop. The rapid expansion of soy frontiers required an exceptional degree of boosterism and investment by national governments, international scientific bodies, corporations, philanthropic entities, and university researchers that invented new sources of demand for soybeans on the one hand, and that prodded farmers to plant their lands with soy on the other. My dissertation analyzes the multi-pronged efforts that drove global soy frontier development to determine why soy was the most rapidly-expanding crop of the postwar era, and to uncover the interests served in the homogenization of vast landscapes under soybean fields. Whereas historians often use the lens of the Green Revolution in wheat, rice, and maize cultivation to examine twentieth-century agricultural change, the case of soy extends both before and after the typical bookends of the Green Revolution narrative, illuminating continuities in the ways in which empires, states, and businesses mobilized agricultural science to exert control over territory and populations.