Revised and updated, this compendium helps readers identify and understand the scope of key government reference sources-traditional books (including publications catalogs and telephone directories); information clearinghouses; and materials in new formats, such as CD-ROMs, datafiles, and Internet sites. The authors focus on free information and depository materials-both readily available through toll-free phone numbers, mail or e-mail requests to agencies, or federal depository library collections. Materials are fully described in annotations that differentiate between similar materials, identify typical citation formats, and note common abbreviations

Describing nearly two million images, this second volume in the series documents the collections of four Smithsonian science and research bureaus: the National Museum of Natural History, the National Zoological Park, the Smithsonian Astrophysical Observatory, and the Smithsonian Tropical Research Institute. See "Photography" for additional volumes.