Multi-agent systems typically consist of autonomous entities, capable of adapting their behavior and interaction patterns in dynamic environments, making them an interesting approach for modeling self-adaptive systems. The interactions among agents, a key challenge in engineering multi-agent systems, are often structured and managed by means of organizations. In previous work we have built a prototype of an organization middleware, which encapsulates the management of dynamic organizations as a reusable service and offers organizations as first-class programming abstractions to application developers. To develop a mature middleware, we face two key challenges: realizing the integration of the middleware with the rest of the system in a disciplined way and assuring properties, such as self-adaptivity and self- healing, of services offered by the middleware. This paper presents a formal specification of an organization and management model for dynamic organizations, a first step in facing these challenges. Both models contribute to the integration of the middleware with the rest of the system. The organization model rigorously describes the main programming abstractions to which application developers have to conform, while the management model can be used to derive specific monitoring and control points required by the middleware to realize self-* properties. In addition, the management model offers a foundation to reason about self- * properties.