This is one of the most boring books you'll ever read.
It contains long lists of HTML elements and attributes and CSS selectors and properties.
Why bother? Why read this book?
Because it provides you with a unique opportunity to learn HTML and CSS, one that isn't available in this form elsewhere.
Its goal is to show you the rough and raw skeleton of HTML and CSS, so that you can focus on that. Elements, attributes, selectors, properties. No explanations, no examples, no context. The raw material.
The idea is that even when you only review this book once, you will already notice things about HTML and CSS that you weren't aware of and couldn't have noticed otherwise.
And still, this is one of the most boring books you'll ever read. Enjoy.