The idea of a an Unmoved Mover or better still a First Cause is fascinating. Just to think that everything has a cause(s) which itself has a cause(s) takes one to a journey backward which we may well be ill equipped to take. This book didn't do much in that domain however, but it rather explained our recent understanding of the cosmos and how from "nothingness" (though with quantum fluctuation which makes the whole idea of Krauss' "nothingness" problematic) a whole universe can come into existence. Frankly, I couldn't help finding the title inappropriate . However, it helped to clear some misunderstandings that I had about the multiverse and the inflation, though the examples he used were not-so-brilliant.
But, I was disappointed with the book because it made serious attacks against philosophy which in my view were unfounded or at best irrelevant especially that he mentions in this very book how Einstein (apparently one of his heroes) was influenced by Spinoza. Sean Carroll beautifully put it while commenting on Krauss' attacks on philosophy:"The point of philosophy is not to be “useful” to science, any more than the point of mycology is to be “useful” to fungi".