Disclaimer: This is my personal opinion about this book and should be considered only that, nothing more.
I know, you might ask that reading this book is just a waste of time because everyone knows how internet works. Well, not everyone. I have spent quite a good time interviewing people for various positions and believe me you will be surprised by the fact that a considerable amount of candidates failed to explain internet. Strange.
This book is a basic one, a book for dummies. This is a book you can read quickly if you think you need an understanding of internet. Overall if you paid even little attention in classroom i do not think this book is for you.
The Internet book by Douglas E. Comer can be read alongside. Both of these will put you in a situation where you can easily answer How Internet works.