Sponsored by the US Department of Health and Human Services, National Institutes of Health (NIH), and the Center for Disease Control and Prevention (CDC), the HIV/AIDS Treatment Information Service (ATIS) offers authoritative information on HIV and AIDS treatment for both healthcare practitioners and general users. The key part of the site is the Treatment Guidelines Library, which contains current and archived federally-approved treatment guidelines, most in both HTML and .pdf formats. Current guideline categories include Pediatric, Perinatal, Health-Care Worker Exposure, Nonoccupational Exposure, Opportunistic Infections, and Tuberculosis. Many of the guidelines are living documents that reflect the present state of knowledge in their category and will be updated in the future. While this section is aimed at professionals, all interested users will find the General Treatment Information section useful. In addition to general overviews of HIV/AIDS treatment, it also covers drug treatments, women and HIV, and special topics. Other resources at the site include a glossary, related publications, a collection of links, a what's new section, and a free email update service.