"HTML5: Up and Running" gives a concise history of web standards that have led to the development of HTML5 which is the next generation web standard. The book then describes all of the details of the HTML5 specification, and how you can use the new features to improve your website. It discusses the following things is particular: detecting HTML5 features, canvas tag, video tag, geolocation, local storage, and new form elements.
The book goes into a ton of detail on each of the topics, but sometimes it drags on about topics that seem completely tangential to the core subject matter of the book. In particular, the book spends a lot of time discussing the history of web specifications and video formats. These topics, while well written, seemed to be somewhat outside of the primary scope of the book. That negative point aside, there is a ton of good content in this book that will help you create the next generation of websites by making use of the amazing new stuff being rolled out in HTML5. There are plenty of code examples and practical use cases for each of the topics that the book discusses, and the book will definitely give you a really good idea how you can improve your existing sites using HTML5.