The National Science, Mathematics, Engineering, and Technology Education Digital Library (NSDL) is the National Science Foundation's (NSF) ongoingeffort to build a comprehensive science digital library." This resource by Carl Lagoze et al. describes the interoperability structure for this initial stage of NSDL's development. Issues of heterogenous metadata management in a central repository, search and discovery services, rights management, and user interface are all addressed. These three articles are required reading for anyone interested in the future of digital libraries and cooperative efforts to harness the educational power of the Web. Note: For information on the Internet Scout Project's involvement in NSDL, see http://scout.cs.wisc.edu/nsdl-reports/.