Between 1846 and 1940, more than 50 million Europeans moved to the Americas, irrevocably changing both their new lands and the ones they left behind. Their immigration fostered an idea of the "land of the free" and yet more than a third returned home again. In a ground-breaking study, Tara Zahra explores the deeper story of this movement of people. As villages emptied, some blamed traffickers in human labour. Others saw opportunity: to seed colonies like the Polish community in Argentina or to reshape their populations by encouraging the emigration of minorities. These precedents would shape the Holocaust, the closing of the Iron Curtain and tragedies of ethnic cleansing while also forming notions of social solidarity, human rights and freedom.