The W3C Semantic Web Deployment Working Group has published the First Public Working Draft of SKOS Simple Knowledge Organization System Primer. SKOS provides a model for expressing the basic structure and content of concept schemes such as thesauri, classification schemes, subject heading lists, taxonomies, folksonomies, and other types of controlled vocabulary. SKOS has been designed to provide a low-cost migration path for porting existing organization systems to the Semantic Web. The primer is intended to help implementors who have a basic understanding of the Semantic Web to use the capabilities defined in SKOS Reference to represent and publish their concept schemes as SKOS data. The Primer aims to provide introductory examples and guidance in the use of SKOS vocabulary features.