Among network designers and administrators, wired Ethernet is a known quantity. Plenty is known about how to build good twistedpair network infrastructures, how to keep them secure, and how to monitor their excess capacity. Not so for the wireless Ethernet networks (built around the IEEE 802.11x standards)these hold much more mystery for even experienced network designers. 802.11 Wireless Networks: The Definitive Guide aims to codify the body of knowledge needed to design and maintain wireless local area networks (LANs). The authors succeed admirably in this, covering what installation and administration teams need to know and digging into information of use to driver writers and others working at lower levels. The only significant detail that`s been excluded has to do with securitya notorious weak point of 802.11x LANs. The authors cover the feeble but widely used Wired Equivalent Privacy (WEP) authentication protocol in detail and devote another whole chapter to 802.1x, which is an emerging authentication scheme based on Extensible Authentication Protocol (EAP). The author has considerable skill in communicating information graphically and does a great job of using graphs to show how communications frequencies shift over time and how conversations among access points and network nodes progress over time. This is indeed an authoritative document. David Wall Topics covered: How IEEE 802.11a and 802.11b wireless networks (also known as WiFi networks) work, and how to configure your own. The framing specification is covered well, as are authentication protocols and (in detail) the physical phenomena that affect IEEE 802.11x radio transmissions. There`s advice on how to design a wireless network topology, and how to go about network traffic analysis and performance improvement.