The philosophy of the social sciences considers the underlying explanatory powers of the social (or human) sciences, such as history, economics, anthropology, politics, and sociology. The type of questions covered includes the methodological (the nature of observations, laws, theories, and explanations) to the ontological -- whether or not these sciences can explain human nature in a way consistent with common-sense beliefs. This Handbook is a major, comprehensive look at the key ideas in the field, is guided by several principles. The first is that the philosophy of social science should be closely connected to, and informed by, developments in the sciences themselves. The second is that the volume should appeal to practicing social scientists as well as philosophers, with the contributors being both drawn from both ranks, and speaking to ongoing controversial issues in the field. Finally, the volume promotes connections across the social sciences, with greater internal discussion and interaction across disciplinary boundaries.