The videos and the source code are open source, meaning they are publicly available. Therefore, you don’t have to buy a book—you can just watch the 14 videos on YouTube (playlist) and go through the code on GitHub (repository).
Pre-order on Amazon (print book): http://amzn.to/1nIknSG
Buy now at Apress (ebook and print book): http://www.apress.com/9781484217504
So if you are beginner to Node, I highly recommend watching the videos and going through projects. If you need results quickly and want to really master Node, Backbone and MongoDB in a short time (or start mastering), then pre-order the book as well at Amazon.com.
PS: If you want to support Apress and me, get the book. I’ll get $1 from each sale.;-)