The document provides background information on immigration to the United States in the late 19th and early 20th centuries. It discusses how employers relied on immigrant laborers from Asia who could not become citizens, as well as temporary Mexican workers. Prejudice against Asian immigrants led to the Chinese Exclusion Act of 1882. Immigrant processing centers like Ellis Island screened newcomers. While immigration was initially encouraged, nativist sentiment grew and Congress passed laws in 1921 and 1924 setting immigration quotas.