CSS: The Definitive Guide
Provides you with a comprehensive guide to CSS implementation, along with a thorough review of all aspects of CSS 2.1. Updated to cover Internet Explorer 7, Microsoft's vastly improved browser, this new edition includes content on positioning, text wrapping (nowrap), lists and generated content, table layout, user interface, paged media, and more.
The -moz selector is still in beta stage for firefox but the ::selection selector is valid CSS3. The CSS validator hasn't been update yet for CSS3.
Kind of nice, doesn't validate with W3C though.