In this chapter, Corsi, Barbera, Dansero, Orlando and Peano present the general theoretical framework for the research described in this volume. They discuss the concept of Alternative Food Networks as presented in the literature and the criteria of “alternativeness” on which it is based (length of the chain, local origin, embeddedness), arguing that the main factor that determines whether a chain can be considered alternative is the quality of the exchange relationship, i.e., the fact that in AFNs the exchange is not only a question of selling a commodity for money, but produces benefits in itself. They review the current approaches to AFNs in different disciplines – economics, sociology, geography, anthropology and environmental sciences – and present the approach followed in this book.