It is rare to run into that one product that impresses technical audiences in the way that ISA Server 2004 has managed to. As I prepared to write this book, what surprised me was not ISA's ability to wow and charm Microsoft-centric environments, but its ability to impress the Microsoft-skeptic crowds as well. These are the ones who have been skeptical of anything coming out of Redmond with "Security" in its titlefor good reason in many cases. So, from its release, ISA faced a seemingly insurmountable uphill battle for acceptance, which makes its success even more impressive.I have had the luxury of working closely with several of the best technologies Microsoft has produced: Active Directory, SQL Server, SharePoint, and Exchange. It therefore takes a powerful product for me to be impressed, and ISA Server 2004 really has done that. ISA functionality is broad, with VPN, reverse proxy, firewall, content caching, and protocol filtering capabilities. Marketing slogans are one thing, but this product really does live up to its billing. I have deployed, administered, and tested ISA Server at organizations of many sizes and functions, from city governments to banks to law firms to technology firms, and have had great success with the product. The breadth and depth of functionality that ISA provides makes my job designing security for these types of environments that much easier.This book is the result of my experience and the experiences of my colleagues at Convergent Computing in working with ISA Server 2004 Standard and Enterprise versions, in the beta stages and in deployment. I wrote this book to be topical, so that you can easily browse to a particular section and follow easy-to-understand step-by-step scenarios. In addition, if you are looking for a good overview on ISA, the book can be read in sequence to give you a good solid understanding of the higher levels of security and functionality ISA can provide.