This book is rich with data and document excerpts that illuminate the complex relationships among ethnicity, religion, and immigration to the United States over a 200-year period. The book uniquely organizes the flow of immigration to the United States into seven chapters covering U.S. immigration policymaking, including the Open Door Era, 1820-1880; the Door Ajar Era, 1880-1920; the Pet Door Era, 1920-1950; the Dutch Door Era, 1950-1985; the Revolving Door Era, 1985-2001; and the Storm Door Era, 2001-2018. Each chapter analyzes trends in ethnicity or national origin and the religious affiliations of immigrant groups in relation to immigration policy during the time period covered.