The HyperDOC hypertext/multimedia service relies upon the World-Wide Web technology developed by Tim Berners-Lee and his colleagues at CERN (Geneva, Switzerland). HyperDOC was initially developed by R. P. C. Rodgers, M.D., who has continued to extend it with the invaluable skills of Suresh Srinivasan. Development was greatly assisted by the appearance of the NCSA Mosaic World-Wide Web browser. The effort has received the enthusiastic support and assistance from numerous colleagues at the NLM and elsewhere at NIH, particularly those within the Computer Science Branch and elsewhere within the Lister Hill National Center for Biomedical Communications (LHNCBC). The original cartoons, logos, and artwork were created by Joe Fitzgerald and Becky Cagle of the LHNCBC Audiovisual Program Development Branch (APDB). Many of the NLM-related photographs were taken by Karlton Jackson of the APDB. Credit for contributions to specific documents or services available via HyperDOC appears in conjunction with the contributed materials.