Eli Lederhendler of the Hebrew University of Jerusalem reviews The Great Departure: Mass Migration from Eastern Europe and the Making of the Free World by Tara Zahra. Between 1846 and 1940, more than 50 million Europeans moved to the Americas, irrevocably changing both their new homes and the ones they left behind. In this study, Tara Zahra explores the deeper story of this astonishing movement of people—one of the largest in human history. Some saw vast opportunity: to seed colonies of migrants like the Polish community in Argentina, to gain economic advantage from an inflow of foreign currency, or to reshape their communities in a new land. In the United States, their migration fostered the notion of the “land of the free.” Globally, 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.