William Petersen describes how ethnic identity is determined and how ethnic or racial units are counted by official statistical agencies in the United States and elsewhere. The chapters in this book cover such topics as: "Identification of Americans of European Descent," "Differentiation among Blacks," "Ethnic Relations in the Netherlands," "Two Case Studies: Japan and Switzerland," and "Who is a Jew?" Petersen argues that the general public is overly impressed by assertions about ethnicity, particularly if they are supported by numbers and graphs. The flood of American writings about race and ethnicity gives no sign of abatement. offers an indispensible background to meaningful interpretation of statistics on ethnicity, and will be important to sociologists, historians, policymakers, and government officials.