I wasn't sure who this book is for after reading the description so this post should help you decide if this book is for you.
If you never used Node.js or any kind of servers side Node.js then you can learn a lot, but you have to know basics of programming. Most of the technologies will be useful in Web Development as well so I can recommend it to Front-End developer who want to learn more about the Back-Ends.
Unfortunately, I expected the book to be harder and more focused on game programming. It was really good to see hard ideas like corrections implemented in simple examples. It was encouraging to see how easy it can be to be implemented regardless of how hard it sounds.
If you are interested in more implementation techniques of the game servers and how those ideas you already know might be implemented there then your best companion is the accompanying code.
Unlike many programming books, the applications actually work and the code is easy to read. Personally I found the code much more interesting than the book.
If you don't know much about programming servers this books is going to be a nice introduction. Everything works and you have working code associated with high-level overviews. I would really like to read it 3 years ago when I was starting with Node.js!