One of the first things to know about this book is that it doesn't try to be a complete reference for computer security, and it keeps it focus very well. It doesn't try to be a computer security book for the top 5% of the technically inclined, either. Instead, it tries to be a computer security book for the masses and covers topics that they'll need to know to keep their computer safe. The book outline why this is important to the average user: your own data will be kept safe and your computer will be kept problem free, and your computer wont be a problem source for everyone else.
The book does a decent job of laying out what it will cover and mostly picks topics that matter most, require the least amount of extra effort to make it happen. The book isn't just for one situation, either, and it covers some home network setups which include wireless routers and such. Overall, it seems to have picked its territory well.
It covers this territory in an OK fashion, which is to say that it gives an adequate treatment to the important topics but leaves a few spots uncovered. I'm pleased that it covers some basic WinXP stuff, like how to secure your accounts and such.
The chapter on passwords was OK, and about what I expected. Obviously these are important, as bots that perform brute force attacks to get in are as popular as ever. The chapter on patching is OK, but seems incomplete. It should have done a better job of covering Windows Update a little more thoroughly (it felt like it stopped short of this important feature) and a bit more on how to use built-in vendor supplied "I have an update available" stuff that is increasingly popular.
Part II is what's probably unique about this book, and gives some of the best meat around for this level of a book. It covers home networking safety (ie keeping the neighbor kid from using your WIFI and keeping your computers safe and usable behind a DSL firewall), email security (both your account credentials and attachment security), and spyware, adware, and general web-browser security. I would have liked to have seen the book advocate (with great reasons) Firefox over IE and Windows Defender in addition to AdAware and Hijack This.
Part 3 is about maintenance and backups, and it's decent. It slips into Linux advocacy in Chapter 12, which we could have done without.
The appendices are good, well reasoned and well executed. The case study and the basics covered complement the book well.
Overall the book does a decent job, and targets the kind of person who would like to know enough to participate in some popular forums and contribute, so they have some technical skills that they're growing. It wont do so well with people who are not very technically inclined, and that's not unsurprising.