The Resource Description and Access (RDA) standard, due to be released this coming summer, has included since May 2007 a parallel effort to build Semantic Web enabled vocabularies. This article describes that effort and the decisions made to express the vocabularies for use within the library community and in addition as a bridge to the future of library data outside the current MARC-based systems. The authors also touch on the registration activities that have made the vocabularies usable independently of the RDA textual guidance. Designed for both human and machine users, the registered vocabularies describe the relationships between FRBR, the RDA classes and properties and the extensive value vocabularies developed for use within RDA.