This handbook on relational sociology covers a rapidly growing approach in the social sciences—one which is connected to the interests of a large, diverse pool of researchers across a range of disciplines. Relational sociology has been one of the key foundations of the “relational turn” in human sciences since the 1980s, and it offers a unique opportunity to redefine the basic epistemological and ontological principles of sociology as we know it. The contributors collected here aim to elucidate the complexity and the scope of this growing approach by dealing with three central questions: Where does relational sociology come from and what are its principal concerns? What are the main theoretical and methodological currents within relational sociology? What have we studied in relational sociology and what are the results?