Murach's HTML, XHTML, and CSS is an excellent introduction to clean, correct, modern (X)HTML and CSS. It is likely to be highly beneficial to novices and advanced beginners.
Each chapter includes a large amount of interesting and helpful diagrams, examples, and technical bullet points to help the reader quickly gain insight into the important points covered.
The cover says "Training and Reference", though my perception is more training than reference. I'd suggest Apress' "HTML and CSS Design Patterns" for use as a reference once you've mastered the concepts in this book.
In short: A very valuable learning resource for beginners to reach level of skill and productivity that allows them to deliver high quality code in a fairly short amount of time.