I will not review the content of this book. Brian Greene is an excellent author, and I have no reason to believe that is is any less brilliant a job than The Elegant Universe. On content, I don't doubt that I'd give it a 5-star rating.My contention with the Kindle edition is that the book is one long chapter. Have fun navigating it. Also, the end notes do not hyperlink as they do in many other excellently formatted books for Kindle. Get the dead tree version if you want to easily reference this book. I immediately returned my Kindle version for a refund and will get the treeware version.