The Computer Science Branch (CSB) applies techniques of computer science and information science to problems in the representation, retrieval and manipulation of biomedical knowledge. CSB projects involve both basic and applied research in such areas as intelligent gateway systems for simultaneous searching in disparate databases, intelligent agent technology, knowledge management, the merging of thesauri and other controlled vocabularies, and machine assisted indexing for information classification and retrieval. Research issues include knowledge acquisition, knowledge representation, knowledge base structure, knowledge visualization, and the human-machine interface for complex systems. Important components of the research include embedded intelligence systems that combine local reasoning with access to large-scale online databanks. CSB research staff include the team that has developed the NLM Gateway, the team that annually produces the Unified Medical Language System (UMLS) Metathesaurus, and members closely involved in the Center's training programs. Staff members participate in the meetings of the Internet Engineering Task Force and in other professional specialty activities. The most current information about the Computer Science Branch can be found at http://lhncbc.nlm.nih.gov/csb/.