The CSS Zen Garden was created as a showcase for CSS design. It shows impressively what can be achieved by separating content from design. In the accompanying book the authors show several aspects of design and how you deal with these aspects in CSS. Each chapter shows several designs that are outstanding in a special field of design.
The book works nicely as an inspiration and explains some techniques that might be interesting for a CSS newbie. Experienced CSS users will not learn that much from it and I have to say that some designs and techniques might already be outdated in this fast-moving internet world. I haven’t done that much in web design in the last years, so I found the book quite inspiring and it’s also great fun to surf through the designs on the CSS Zen Garden Website. If you’re looking for inspiration that should be the first place to go. If you also love books than go and get this one.