Before purchasing this book I had a thorough understanding of HTML. I also knew how to create websites with tables in Dreamweaver, which is how my college course taught me (ugh). I did use CSS, but only in Dreamweaver to manipulate text, background, and header styles. So I bought this book with the intention of creating websites in a more efficient way. I wasn't exactly excited to learn and write scripting languages due to my tendency to be more of a designer than a developer, but this book made the process enjoyable.
The book provides the underlying principles of HTML and CSS, and then guides the reader through the development of a simple scuba diving site. After completing the book and the site I felt I had a good grasp on the basics of CSS and HTML. It was simple to understand and the author does a good job of teaching how to think about how things interact, instead of just copying code. He also teaches how to stay organized in the process. Perhaps one of the most useful parts of the book is how many references he provides. The scuba site was simple, and in my opinion, a horrible design, but he gives enough to go on for more advanced stuff.
A month after completing the book I began designing and developing my first website for a local massage business, and after that a site for a political organization. I was staying up late into the wee hours trying to figure out how to get things to work the way I wanted on both of these sites, and this book didn't provide all the answers, but it gave me the foundation to build upon and understand what other web designers/developers were talking about on other forums, sites, blogs, etc.
Overall, a good book to get started.
Tyler