Book excerpt: This book brings together two traditions of thinking about social ties: sociological theory on sol idarity and anthropological theory on gift exchange. The purpose of the book is to explore how both theoretical traditions may complete and enrich each other, and how they may illuminate transformations in solidarity. The main argument, supported by empirical illustrations, is that a theory of solidarity should incorporate some of the core insights from anthropological gift theory. The book presents a theoretical model covering both positive and negative--selective and excluding--aspects and consequences of solidarity.