To cooperate or not?. This is the question that participants in Community Development Projects pose to themselves on each venture. It has not an easy answer since cooperation is costly as Alejandro Natal shows in this book. The author describes how communities have to devote time and effort to actually produce collective action, manage it and prevent freeriding and other individual and colective conflicts. The Costs of Cooperation is an interesting concept that the author develops to argue that Community Particpatory Development as it has geen generally thought. The insights of this book may offer interesting points for reflection to NGos, development practitioners,donors and sccholars interested in the field of development adminsitration.