Sybil is a web-based software package for comparative genomics. It was developed by the Bioinformatics department at The Institute for Genomic Research (TIGR) and development continues at the J. Craig Venter Institute and Institute for Genome Sciences (IGS) at the University of Maryland Baltimore's School of Medicine. The project has been funded by a variety of sources including: The National Institute of Allergy and Infectious Diseases (NIAID) as part of the NIAID Bioinformatics Resource Centers (BRC) for Biodefense and Emerging or Re-Emerging Infectious Diseases and PATH an organization supporting research in Streptococcus and Neisseria vaccine development. While still under development, several of the Sybil tools have been used internally at TIGR, the JCVI and IGS by research projects that involve comparative genome analysis. See the SCREENSHOTS section below for examples of the types of analyses and displays that the system currently supports, or follow the link to the Demos page to interact with a live (albeit scaled-down) version of the system, running on a demonstration database that contains genome sequences, annotation, and comparative data from ten Streptococcus pneumoniae genomes. If you have any questions or suggestions, please contact us using the sybil-info mailing list. Registration not required.