As its title suggests, this is an introductory text. It makes a decent beginner's reference as well, but assumes little to no knowledge of web technologies and is clearly geared toward non-professionals. That said, it is a very well done introduction to Web 2.0, including some discussion of HTML5, and has a good breadth of coverage.
Similar to other Sam's books (most of which are great for beginners) the text is divided up into chapters that take about an hour to finish. It starts with very simple stuff such as the basic HTML/CSS tags and progresses to advanced topics like AJAX and scripting. If you've been awake during the last ten or so years, you can safely skip the introduction. Most of the common HTML 4.x tags are covered in depth, including some that have fallen into disuse. Notes are made regarding what will be supported in HTML5, but most of the discussion is limited to compatibility. This isn't a book on HTML5 or CSS3, which makes sense as of now since neither of those are widely supported yet. Aside from some brief discussion of the <video> tag, you probably won't learn much about the new standard itself.
Each chapter is built around a short exercise with code snippets and explanation. It is done in a step-by-step manner that's very easy to understand.* Additional reading and exercises are noted at the end, if you care to learn more. Aside from HTML, topics range from page layouts to basic scripting (JS/PHP), embedding movies, and content handling. It even touches on some frameworks like JQuery and swfobject. The authors generally shy away from browser-specific optimizations and syntax, which is probably a good thing as some of these can cause serious issues. They also discuss some legacy features that you might see (e.g. frames) but also do a good job noting what you should and shouldn't be using. The authors don't promote any particular browser, save for a brief note at the start that they recommend Firefox for use with this book. While I agree that Firefox is good for development- especially if you do JS- it's an unfortunate fact that IE still has the most market share and is also by far the least forgiving browser. If you can get something to work in IE, it will most likely work with anything else- but the opposite is far, far from true. On that note, there's not much discussion of browser quirks (rather, the authors point you to places like quirksmode.org, which is fine if you really care to know) but rather emphasis on writing well-formed pages that will most likely work.
*(I should note, however, that it just so happens I am a web professional, so take this with a grain of salt)
As with most general IT books, this one takes the scattergun approach and doesn't go very in-depth into any particular area. Some rather important things, like social network integration, are barely touched upon. Personally, I think this is for the better- you can spend months learning just one aspect of web publishing (and make a lot of money off it, to boot) so this sort of book gives you an idea of what's out there. If for whatever reason you only care about a particular topic, go find a book specific to it- more likely than not, there's probably a few dozen to pick from. Or if you'd rather save some money, go online: in most cases there are TONS of free web resources and tutorials for those who want to venture a bit deeper. This book just gives you a great place to start.
Easy to follow with well-structured examples.
Good coverage in topics, breadth-wise.
Solid foundation of best-practice and design guidelines.
Not much coverage of HTML5, which you might expect from the cover/description.