I must say, that this book is written by professionals. I have tons of books about SQL, and this book is among of the best.
What is important: authors waste no time on less important stuff. Every chapter, every paragraph in this book is like a sniper shoot.
All clear, all design philosophy is explained. Caveats are pinpointed, working examples provided.
This book will greatly help novices, and also will be useful for advanced users.