Macintosh's tenth Operating System (or MacOS X) is, Langer tells us, a major revision, with the elimination of system extensions and control panels, a default set up for multiple users, new log out command, new system preference application, new default font, new window controls, etc. Langer (she's the author of many computer books) guides the reader through installation and other basics in the first chapters, then describes the Finder, file management, applications, software, TextEdit, printing, connecting to the Internet, using Sherlock, and setting system preferences, all with frequent screen shots for illustration. Annotation c. Book News, Inc., Portland, OR (booknews.com)