The idea of the United States as a nation of immigrants is at the core of the American narrative. But in 1924, Congress instituted a system of ethnic quotas so stringent that it choked off large-scale immigration for decades, sharply curtailing arrivals from southern and eastern Europe and outright banning those from nearly all of Asia.

In a riveting narrative filled with a fascinating cast of characters, from the indefatigable congressman Emanuel Celler and senator Herbert Lehman to the bull-headed Nevada senator Pat McCarran, Jia Lynn Yang recounts how lawmakers, activists, and presidents from Truman through LBJ worked relentlessly to abolish the 1924 law. Through a world war, a refugee crisis after the Holocaust, and a McCarthyist fever, a coalition of lawmakers and activists descended from Jewish, Irish, and Japanese immigrants fought to establish a new principle of equality in the American immigration system. Their crowning achievement, the 1965 Immigration and Nationality Act, proved to be one of the most transformative laws in the country's history, opening the door to nonwhite migration at levels never seen before—and changing America in ways that those who debated it could hardly have imagined.