Unlike most of the CSS books floating around out there currently, "Eric Meyer on CSS" gives you practical projects to work through, and apply CSS to, talking you through the whys and wherefores all the way. It takes you all the way from transforming an existing HTML table-based layout into a more streamlined structure using CSS, all the way up to bleeding edge design concepts that will be more and more feasible as the browsers catch up to web standards.
I would not recommend this book to someone who has absolutely no experience or knowledge of CSS (maybe check out the tutorials in your HTML editor, or look at some of the online tutorials at Webmonkey.com before diving into this book).
And, for intermediate users (you've been using stylesheets for awhile, maybe just to handle typography), I'd recommend also getting Eric Meyer's "Cascading Style Sheets: The Definitive Guide" for a more in-depth study of the CSS specs, though you can make it through most of the concepts presented here with just the information given with a little extra mental effort and perseverance.
The writing style is conversational and entertaining, and there are clear reasons given for everything. Meyers is definitely trying to teach you to fish rather than hand you a mackeral and send you on your way.
I really enjoyed that the book was in full color, and had a lot of visual aids -- New Riders is great for this.
If you're interested in the possibilities of web design using CSS, this book is well worth the price of admission.