It's okay, but very convoluted
This book does a good job covering the details of the various protocols and standards used in different types of VPN's. But the same information can be pulled in nearly the same format from RFC's.After the first few chapters, the book get's confusing and is sometimes wrong when the author describes the process behind setup of a IPSEC VPN connection (there's a couple of places where AH is confused with ESP). Beyond that I found the book hard to follow because it lacks a broad comparison between different types of VPN's (why you would want to choose one type over another and so forth).But even more irking was paying [item price] for a book that's full of typo's and repetitive sentences.