As scientific work becomes more complex, contextual information is critical to enable its use. We have developed the concept of Knowledge Spaces that manage such information and scope the space of data, metadata, and algorithms relevant to the work of a Virtual Organization. This enables scientists to produce and manage descriptive metadata, process description, data provenance, as well as VO-specific quality assertions, vocabulary mappings, inferences, computation, approximations, and security policies. We have developed middleware and cooperating applications that demonstrate the potential of Knowledge Spaces in the production and dissemination of scientific data.