For more than three decades, Ethnic Americans has been hailed as a classic history of immigration to America. Leonard Dinnerstein and David M. Reimers begin with a brief overview of immigration during the colonial and early national eras (1492 to the 1820s), focusing primarily on the arrival of English Protestants, while at the same time stressing the diversity brought by Dutch, French, Spanish, and other small groups, including "free people of color" from the Caribbean. Next they follow large-scale European immigration from 1830 to the 1880s. Catholicism became a major force in America during this period, with immigrants—five million in the 1880s alone—creating a new mosaic in every state of the Union. This section also touches on the arrival, beginning in 1848, of Chinese immigrants and other groups who hoped to find gold and get rich. Subsequent chapters address eastern and southern European immigration from 1890 to 1940; newcomers from the Western Hemisphere and Asia who arrived from 1840 to 1940; immigration restriction from 1875 to World War II; and the postwar arrival and experiences of Asian, Mexican, Hungarian, and Cuban refugees.

Taking the past fifteen years into account, the fifth edition of Ethnic Americans considers recent influxes of Asians and Hispanics, especially the surge in the Mexican population, and includes expanded coverage of nativist sentiment in American politics and thought.