Traditionally reserved for literary scholars and linguists, practices of translation have only recently caught the interest of social scientists. Limiting their analysis to one type of translation practice, the translation of books, the authors present some of the main questions, concepts and findings of this emerging research domain. Three levels of analysis are addressed. The transnational level is concerned with documenting and explaining the international flow of book translations and the changing structure of the world market. The level of producing translations concerns the publishing industry, and the economic, political and cultural dimensions of its functioning. The level of selecting, importing and valuing translations is concerned with the decision-making of both publishers and consumers, and in particular with the way they deal with issues of linguistic diversity, cultural proximity and economic as well as cultural constraints. Many of the analytical issues that come up are structured by the opposition between an economic analysis, based on the aggregation of rationally calculating agents, and a sociological understanding, grounded in a multidimensional analysis of power relations.