Although it is the flexibility to develop and administer distributed applications, the conceptual model underlying the different configurations is only implicit. To fix the problem, Semantic Management of Middleware contributes an ontology-based approach to support the development and administration-based middleware applications. Therefore, its description may be asked, may foresight required actions, or may be checked to avoid inconsistent system configurations. The book builds a rigorous approach to provide declarative descriptions of components and services a defined meaning by specifying ontological foundations and by showing how the foundation can be realized in practical systems, up-and-run.