We demonstrate MMS, a system for storing and managing a variety of metadata in a simple, elegant and uniform way. The system is based on two observations. First, that the relational model augmented with queries as data values is a natural way to uniformly model data, arbitrary metadata and their association. Second, that relational queries with a join mechanism augmented to permit matching of query result relations, instead of only atomic values, is an elegant way to uniformly query across data and metadata.