Caveat: I was recently given this book and though it now refers to the former stable Debian system "Sarge", I thought I'd read it to see what it has to say. Debian books are less common than some other distros, so even though it's out of date I thought I should still publish a short review. It is also a popular book on Amazon with plenty of positive comments.
This is a highly ambitious book that attempts to cover the whole Debian 3.1 system for beginner to advanced user (though in the Preface they actually suggest beginner to intermediate), from the command line via server functionality to complex GUI office applications and games.
I tried to like this book but ultimately I'd have to say it is fatally flawed. The scope is too large to be adequately dealt with.
It repeats the early history of UNIX and Linux for the beginner, wasted pages for an intermediate or advanced user, while at the same time digging around the innards of Exim and BIND well above the abilities of the beginner.
The section on the kernel netfilter/iptables firewall is particularly weak as is the whole security section which while okay in what it says is just to vague to be much help.
In some respects the book is good, the authors very quickly demonstrate the use of su and then move onto sudo, and they don't do dwell on obsolete tools too much. However the inconsistency of the book means that I'm not sure how really useful the book is.
For the beginner, some sections are good but in others there is insufficient explanation, and a beginner would quickly struggle. For the intermediate user, the basic sections are too basic and the advanced sections are too patchy, some are okay others are just to basic to be of any use. For the expert I say this book is of little value.
This isn't a bad book, it's just not a good book. Either the scope should have been reduced allowing the authors to focus the book better, or it should have been broken into two books, "introductory" and "advanced". There are also numerous typographical errors, I fear the problem is not the authors technical skill - which is not in doubt, rather the editor/publisher who has not correctly focused and edited the book.
Obviously Debian stable has now moved on from 3.1 to 4.0, which given the superficial nature of much of the book means it's not too out of date. However, the included CDs are now quite obsolete and though it is easy to upgrade to the current version that is not a topic discussed in the book.