Don't waste your money on this book. You can find information 100x better than what he is offering on Wikipedia.
Basically, the book is all about what is Ethereum, why its good, every single book out there talks about the PROS of cryptocurrency and this one is no different but the worst part is that it doesn't explain you anything.
The format is horrible while I don't care about the formatting I believe in good information this book contains no good information that you can use today and make some money.
As I said if you wanna burn your money on this book then go ahead do it, if you value your money then just search what is ethereum in Google and you will find everything you need to know and much more than what is offered in this book.
I would give it -5 out of 5 but given I can't I gave it 1.
Stay away and do not buy this book there are better books and articles on the topic.