From the site:
The HTML5 spec is 900 pages and hard to read. HTML5 for Web Designers is 85 pages and fun to read. Easy choice.
HTML5 is the longest HTML specification ever written. It is also the most powerful, and in some ways, the most confusing. What do accessible, content-focused standards-based web designers and front-end developers need to know? And how can we harness the power of HTML5 in todayâ€™s browsers?
You can buy a copy from here.