Paul Schor has written a superb book on the history of population counting in the American census since 1790. The story is told in depth, systematically and comprehensively, using deep archival exploration of government sources, explication of long-forgotten debates about the supposed inferiority of people from some 'races' or 'national origins' compared to others, and the alleged threats of people from various parts of the world to the true American experiment. It's a cautionary tale in the context of our current policy questions about immigration, citizenship, racism, and the future of American society