First published in three volumes in 1988, Dan L. Thrapp"s comprehensive work has earned the praise and recurring attention of scholars, researchers, and general readers curious about the important figures of the American West. Now available on CD-ROM, the Encyclopedia has been updated and contains more than five thousand entries. The button-driven format allows quick retrieval of individual names, as well as full-text searches (with the ability to perform more advanced Boolean searches), context indexes with hypertext links, and more. Search terms found in the text are highlighted upon retrieval for fast identification. The specifically designed screen typeface is easy to read. A user-friendly interface and extensive cross-referencing make the CD-ROM a powerful tool.