I did not get very far into this book. Despite the author's stated intention in the introduction that this book was intended for "lay" readers as well as students... it isn't. I have an undergraduate and a graduate degree, with a wide sci-fi reading history and one college-level astronomy class. Even a few pages into the first chapter, I could see I would have to take notes if I was going to continue. The writing was pretty academic, not really approachable for the average member of the public. That style is fine, but know your intended audience. Not for me.