CD-ROM, in plastic shell case, offers online access to the parent text of the same title, 20th edition, c2005. Contains more than 56,000 definitions with hyperlinked cross-references and expanded disease entries. Previous edition: c2001. System requirements: Palm OS: 11MB Free Space Required; Windows, Pocket PC 2000, 2002, 2003: 11MB Free Space Required. Text also available.