This is one of those "essential, have to have" books. I just got through all of the examples and finished building out a 3-tiered snort network for the company where I work as a senior security engineer. We previously had some older, expensive, ISS realsecure equipment in place, and I made the case to managment to replace the RealSecure stuff with open-source Snort. It wasn't that hard, the maintence cost for an upgrade was going to be more than my whole entire Snort-based design. My company had good experiences with apache on red hat, so it wasn't a super hard sell. Times are tough, and managment is looking for ways to cut costs.
This book got me there. I was able to get the meaty technical details I needed, and couldn't find answers to online. Im a highly technical person, Im no (dummy) who gets scared of the command line. Id scoured the snort.org website, mailing lists, newsgroups, securityfocus lists, but they lacked in a lot of areas. Especially, the online articles dont talk about using snort in a corporate or enterprise-size setting. I picked up this book and I was able to put in a very highly effective tuned snort install. I also have moved on to advanced topics, like creating my own custom rules that apply only to my company's network. I use these 20 or so rules to catch traffic that is not supposed to be on my network, but might be normal somewhere else, so there is no offical snort.org rule for them.
In short, this is the best book ive read in a few years, at least for a technical book.
