This Services project is developing a suite of "best practices" documents and resources to foster reusability and interoperability of NSDL holdings. Making NSDL content easier to use in multiple settings (reuse) and more capable of being used by common authoring tools and delivery environments (interoperability), increases its impact and value. But reusable, interoperable content has different design requirements than traditional Web content. This project is synthesizing and disseminating the body of research and practice that has built up in this domain in order to foster its application. Major objectives include: creating and disseminating general NSDL guidelines and recommended practices for designing reusable content and using existing tools to do so; creating and disseminating specialized versions of these guidelines and practices tailored to the methods used and issues faced by the ENC, MERLOT and MathDL user communities; conducting workshops on content reuse and interoperability; and developing recommendations for how collections can expose reusable content in searches. All resources produced by this project are applicable to the entire educational community.