I work on the social and political history of modern Europe, especially France, and on the relationship between the continent and its colonial hinterlands. I have published a book on immigration control and the transformation of citizenship in interwar France and am part of a team preparing a concise edition of Worlds Together, Worlds Apart (Norton), contributing a chapter on France to The Oxford History of the African Diaspora and a chapter on the interwar years to a Franco-Algerian volume to commemorate the fiftieth anniversary of Algerian independence, Histoire de l'Algérie coloniale (La Découverte/Barzakh). My current research concerns the spread of tuberculosis from France to Algeria and back, and efforts to combat it, from 1830 to the present.