Does a company have to do it itself or have it done: must it use its financial resources and organizational know-how to carry out a task or entrust its execution to another company (possibly specialized in this activity)? When it decides to have it done, how should it manage its relations with its suppliers, subcontractors, outsourcers, etc.? And when an organization decides to do so, how should it organize itself? These questions have received a lot of attention in recent years from management specialists and economists. In this brief, I propose an overview of the elements of response provided by the economy of organizations.