This book is awesome : The Truth About HTML5. I read it in two sittings and I spent a good deal of the time just cracking up. I agree with almost everything he talks about in the book.
I’ve been teaching html5 classes for the last few semesters and I’ve had a great time doing. I have however been very careful about what things I tell my students they can use – which things to use polyfills, shims etc… for and which things they should just learn about but avoid at the moment. I was happy to see that these same things were described in great detail in this book. The book also does a great job of giving some history about certain features of html5. I highly recommend The Truth About HTML5 it was a great read.