The NASA Astrophysics Data System (ADS) Web site, which is hosted by the Harvard-Smithsonian Center for Astrophysics, is described as a Digital Library for Physics, Astrophysics, and Instrumentation. ADS maintains four bibliographic databases containing more than 3.2 million records that can be searched or browsed by various interfaces including a Journal/ Volume/ Page Service, Table of Contents Service, Article Service, Scanned Historical Literature Service, and a Scanned Books Service. The article service, for example, allows users to view the latest tables of contents from major journals including Astronomy and Astrophysics and Planetary and Space Science. As a resource for researchers and academics, the site does a good job of providing easy access to potentially valuable information.