By the end of the 20th century, the ethnic question had resurfaced in public debates. As a result of conflicts interpreted from an ethnic perspective (the Balkans, central Africa), nationalist struggles (the Basque country, Quebec, Belgium), and demands for recognition and political representation by new ethnic minorities, every country had been affected by what is commonly known as cultural pluralism. This resurgence or extension of the salience of ethnicity in most of the societies around the world can now be found not only in public discourses, policy making, scientific literatures and popular representations, but also in the pivotal realm of statistics. This book explores the ethnic and racial classification in official statistics, as a reflection of the representations of population and an interpretation of social dynamics through a different lens. Spanning all continents, the book's chapters discuss how ethnic and racial classifications are built, their (lack of) accuracy and their contribution to the representation of ethnic and racial diversity of multicultural societies. This book was originally published as a special issue of Ethnic and Racial Studies.