John Allsop's book provides an excellent overview of the issues associated with modern, standards-based web development. It is not a text book in the sense that one learns the details of writing markup in X/HTML, presentation in CSS or DOM programming in JavaScript. Rather, it is a high-level survey of the issues in the field.
The target audience is web designers. The conversational tone makes the concepts covered easy to grasp. That coverage is incomplete, though, given the breadth of material, and one of the most useful facets of the book are the extensive references to online resources. Programmers and engineers may be less satisfied with the less rigorous approach taken by the author.
The biggest draw back to the book is that it numerous errors. Particularly in chapters with lots of code examples, there is often a discrepancy between the text and the associated code. I searched the author's site, the book's site, and the publisher's site, but was unable to find a published errata. For this reason, I rated the book one star lower than I other wise would have.
This book (and its companion, Designing with Web Standards) are great resources for the modern web developer. People who have been in the industry for years are prone to carry over methods for dealing with web design issues that do not stand the test of time due to difficulty maintaining such solutions. These two books server to educate both veteran and novice web developers on how to create and maintain websites in such a way that they support rapid development & maintenance while focusing on accessibility across multiple platforms. In addition, they very clearly explain why every web site doesn't need to look the same in all browsers (another old notion) and cover how you can bring a rich experience in newer browsers while also gracefully degrading on older browsers to a less-rich but fully-functional and attractive experience.
Great overview of pretty much anything related to web standards. It's concise, straight to the point, doesn't get into details but doesn't gloss them over either.