HTML5 Cookbook is a 250 page book on HTML5 Web Design and Web Development. Most of the book focuses on HTML5 Markup and then at the very end it discusses more HTML5 Programming features like Geolocation, Canvas, Web Sockets, Web Workers, Drag and Drop, and Local Storage. It does a good job discussing the new markup and programming features of HTML5, but personally I think you'd be better off purchasing other books like HTML5 The Missing Manual and Head First HTML5 Programming.
HTML5 Cookbook does a really nice job covering the basics of HTML5 Web Design and Web Development. Mostly it covers the HTML5 Markup, such as:
Overall it packs a nice punch in the short amount of pages. However, most of this can be found on the Internet for free at places like Dive Into HTML5 or HTML5 Doctor. Personally, I think HTML5 The Missing Manual goes into the topics much more deeper if you are really interested in the new markup in HTML5.
Although I enjoyed the book, I just don't think it is the best book out there on HTML5 and a lot of what is in the book can be found for free on the Internet. It also tries to be like a cookbook, but the recipes in the beginning aren't really recipes. Overall, I think you'd be better off reading the books and free HTML5 tutorials mentioned above.