Shockingly short on implementation details, Virtual Private Networks for Dummies tries to craft a scattershot collection of facts and references into an introduction to virtual private networks (VPNs). That"s not to say that this book is insubstantial, because it"s not; probably, you"ll learn something about networking, cryptography, authentication infrastructures, and other aspects of VPN engineering. Also, it"s done a good job of compiling references to VPN resources on the Internet, so you"ll have plenty of surfing to do. But it never explains how to build a VPN--or even the simplest laboratory simulation of one--and that"s precisely the kind of how-to information that buyers of this book will want. True enough: every situation that calls for a VPN is different; and, if the book had shown how to implement a VPN with one turnkey solution, users of the others would complain. But even the narrowest example would have been better than some of the stuff that fills these pages. At one point, the reader is walked through the process of encoding and decoding a plain-text message--by hand--by using a shared private key. Spare us, please. The book gives the vital Layer 2 Transport Protocol all of two short paragraphs. Sections on public-key encryption and digital certificates do a good job of unraveling perennially misunderstood processes, but they don"t offset the lack of details on VPN. --David Wall Topics covered: Aspects of virtual private networks (VPNs), organized to get potential VPN implementers thinking about security and other design issues. Specifically, Public-Key Infrastructure (PKI); digital certificates; turnkey VPN packages; and a lot of general stuff about what VPNs are good for, and how to design a good one.