This book fits in nicely between reference works like Eric Meyers "Cascading Style Sheets: The Definitive Guide" and technique books like Dan Cederholm's "Bulletproof Web Design". At first glance, this rather unassuming book contains pretty basic information about the applications of CSS. However, this book deserves a careful reading, as it is packed with excellent explanations and examples.
"Cascading Style Sheets" isn't full of flashy illustrations, but the examples are well thought out and present the ideas well. The chapter on layout ("Boxes, Boxes, Boxes") contains the best explanation I have seen on how layout boxes function in CSS. If you've been wrestling with understanding the difference between absolute and relative positioning, and how to use these values to make stable layouts, this book is for you.
The chapter on typography is an excellent resource for developers who may not have had the chance to study this essential subject. The authors present theory and application of good typographic practice (which is often ignored in current web design).
The chapter on browser bugs ("Cross-browser CSS") summarizes the current knowledge on cross-browser compatibility very well, and provides rock-solid workarounds for those thorny problems.
Last but not the least, the chapter "CSS Design Projects" will give you some solid examples to apply to your own designs.
There's quite a few good books out there right now on CSS, and quite a few not-so-good books; how is one to choose? Well, this book should be at the top of your shopping list--it's a rich, detailed, and extremely well-written book about the subtle craft of web design with CSS.