Book excerpt: The Microfoundations of Diaspora Politics examines the various actors within and beyond the state that participate in the design and implementation of diaspora policies, as well as the mechanisms through which diasporas are constructed by governments, political parties, diaspora entrepreneurs, or international organisations. Extant theories are often hard-pressed to capture the empirical variation and often end up identifying ‘exceptions’. The multidisciplinary group of contributors in this book theorise these ‘exceptions’ through three interrelated conceptual moves: first, by focusing on understudied aspects of the relationships between states as well as organised non-state actors and their citizens or co-ethnics abroad (or at home - in cases of return migration). Second, by examining dyads of ‘origin’ states and specific diasporic communities differentiated by time of emigration, place of residence, socio-economic status, migratory status, generation, or skills. Third, by considering migration in its multiple spatial and temporal phases (emigration, immigration, transit, return) and how they intersect to constitute diasporic identities and policies. These conceptual moves facilitate comparative research and help scholars identify the mechanisms connecting structural variables with specific policies by states (and other actors) as well as responses by the relevant diasporic communities. This book was originally published as a special issue of the Journal of Ethnic and Migration Studies.