This is supposed to be a Pro book so you would expect something that goes a bit deeper than a beginner's guide. Even so, Chapter 1 is allowed to be a basic introduction, but it really doesn't do a good job. Why have a very long listing of what an HTML5 page might look like? It's just a waste of space. At the end of the chapter you really aren't any the wiser and you might even be worried by the claim that HTML5 won't be finalized till 2022 - true but irrelevant.

Chapter 2 is an introduction to the Canvas element. It isn't a particularly advanced explanation and only gets even slightly technical when it discuses working with pixel data.  The chapter finishes with a simple example. Overall this isn't hardly a "pro" look at Canvas in that it doesn't explain how you can make use of it in any clever or creative way - no modifying videos, no use of Canvas for custom controls etc.

The next chapter is new in this edition and covers SVG graphics at about the same level. After explaining how to use tags to create SVG images, the book suddenly switches to manipulating the DOM without much discussion. The final example is over-long and uses up too much space.

Chapter 4 is on audio and video and doesn't go anywhere that an introductory book wouldn't. The same is true of the Geolocation API covered in Chapter 5.

From here the book moves onto more technical topics - the communication APIs, the forms API, web workers, storage APIs, offline web applications and the future of HTML5. The other completely new chapter in this edition is Chapter 9 on drag-and-drop.

If you have the first edition of this book then it certainly isn't worth buying a new copy for the two additional chapters - look it up on the web. However, it is an improvement on the first edition as long as you are clear that this isn't really a "pro" or a programmer's guide to the new HTML5 technologies. It is, however, more than a beginners guide. The explanations are mostly clear and simple and the initial examples are short and helpful. The longer examples are less successful because they tend to cover nothing new and simply repeat the same material. The book gets better as it goes on but it never explores the material beyond an introductory level.

If you are looking for something that is slightly more than beginners level then this might suit your requirements, but I don't think it deserves the "Pro" in its title.