The Cognitive Science Branch (CgSB) of the LHNCBC conducts research and development in information systems informed by research in the mechanisms underlying human cognition. Important research areas encompass the investigation of several techniques, including linguistic, statistical, and knowledge-based methods for improving access to biomedical information. Branch members have developed and continue to augment SPECIALIST, an experimental natural language processing (NLP) system for the biomedical domain. The SPECIALIST NLP tools facilitate natural language processing by helping application developers with lexical variation and text analysis tasks in the biomedical domain. Branch members also actively participate in the Unified Medical Language System (UMLS) project and lead the NLM Indexing Initiative, whose goal is to develop automated and semi-automated techniques for indexing the biomedical literature. The Branch conducts research in digital libraries and collaborates with the NLM History of Medicine Division on Profiles in Science, a project to digitize collections of prominent biomedical scientists. Several Branch projects address the challenges involved in providing health information to consumers. Branch staff developed and continue to enhance the ClinicalTrials.gov Web site that links patients to medical research and promotes public awareness of the role of clinical trials; and the Genetics Home Reference Web site, a rich resource for understanding how genetics affects human health. The most current information about the Cognitive Science Branch can be found at http://lhncbc.nlm.nih.gov/cgsb/