Between 1846 and 1940, more than 50 million Europeans moved to the Americas in one of the largest migrations of human history, emptying out villages and irrevocably changing both their new homes and the ones they left behind. With a keen historical perspective on the most consequential social phenomenon of the twentieth century, Tara Zahra shows how the policies that gave shape to this migration provided the precedent for future events such as the Holocaust, the closing of the Iron Curtain, and the tragedies of ethnic cleansing. In the epilogue, she places the current refugee crisis within the longer history of migration.