After throwing down the gauntlet to IBM AS/400 users by asserting that they utilize half of the system's capability, Dawson (technical editor, Midrange Computing Magazine ) offers an olive branch via techniques to optimize the user-friendliness of what he extols as this "beautiful operating system" powering an increasing number of client- server networks. After an introduction to systems programming for users with some familiarity with either the basic CISC or new RISC- based models the author delineates ways to create new commands, apply security tools, accelerate database jobs, customize existing software, manage APIs, and optimize system performance and configuration. The disk that the book claims should be included can probably be obtained from the publisher. Annotation c. by Book News, Inc., Portland, Or.