In this fantastically detailed book, Eric Meyer explains the basics of css and systematically elaborates on each css property, their scope, and values. Whilst the book is not designed to be read as a guide or an introduction, it does make an excellent reference for those times when you need definitive information on a particular css property.
If you're looking to learn about css, I wouldn't recommend relying on this book alone; buy yourself a real beginner's guide, and maybe get this as a reference tool for when you need to clarify something. As I learnt more about css, I found often found myself flicking through the book and having moments of realisation when paragraph or two would clarify something I'd read elsewhere. That's the sign of a good reference book.
Some people may find the book a little heavy going to begin with. I don't think the book has been designed with the intention that the reader go through it cover to cover in one go. I found that reading a lot of the book at once left me with a lot of questions: these were answered through practical experience with css, and through other, less detailed, introductions. However, I do feel as though the difficulties I had were a result of my lack of understanding rather than any real problem with the book itself; it's still the one book I'll turn to when the others don't answer my questions.
All in all, this is a great book: it won't walk you through your first steps in css, but it does provide exactly what you need when you're lost and need some real answers. If you're new to css, pair this book up with a well-rated introductory text, and you'll be all set to go. For those who have some practical css experience, I'd recommend this as a great reference tool, without hesitation.