The engagement to produce a Master Plan for the redevelopment of military areas (barracks and service areas) constitutes an interesting example of the problems connected with the reuse of land and property assets used by the Ministry of Defence. The essay describes the context in which the planning process was introduced, the characteristics of the military areas to be redeveloped and the complex affairs which led to the suspension of the Master Plan after the conclusion of the first exploratory stage. The story told enables some general considerations to be made on four subjects: the more or less particular nature of military areas compared to other types of underused areas; the great uncertainty over the rules and strategies of the actors; the potential role of municipal administrations in the management of these processes; the forms of knowledge in use and the skills needed to manage them effectively.