Scott Mueller has long been known for the quality of the personal computer hardware reference books he writes. Upgrading and Repairing PCs, now in its 12th edition, remains relevant even as the personal computing market is changing faster than ever.This book represents the most comprehensive single source of information on what used to be called IBM-compatible PC hardware. Look here for data (useful to repair technicians) about processors (e.g. Intel's Itanium and AMD's Duron parts), memory (e.g. RDRAM and DDR SDRAM), video cards, disk drives, removable storage media of all kinds, and network interface cards. If it plugs into a PC, Mueller addresses it.A new emphasis on networking makes an appearance in this latest edition. Whereas earlier versions of the book more or less stopped at the PC case, this one explores the technology underlying cable modems, Digital Subscriber Line (DSL) connections and other high-speed data communications options. It also explains how to make all the custom-length Ethernet cables you want--a simple but valuable addition. Builders of home and small-office networks will probably wish for more coverage of turnkey firewall hardware, but since most of these devices aren't based on the PC platform, their absence is understandable. Mueller ties up the hardware-related discussion in a well-illustrated chapter on scratchbuilding a PC. It's solid work, though it would have been even better if he'd spelled out "best of breed" components by make and model. --David Wall