Quantum Physics is foreign and doesn't make much sense to most people. Sean Carroll, as usual, does a great job explaining aspects of it and his preference for the Many Worlds Theory. It's not an easy read for those with no knowledge of Quantum physics but it is also not extremely difficult if one takes their time with it; Carroll tends to get his general point across in any case. A minor improvement for me would have been including some actual examples of measurement and as it relates to the Scrodinger equation would give a bit more of a concrete feel to how the equation is used in physics (for us non physicists). More importantly, the topic and where the author goes with the search for a Theory of Quantum gravity, is a very nice idea that could be incredibly important. The best 'interpretation' or theory of quantum mechanics potentially contirbuting to a theory of quantum-gravity is likely the next major breakthrough in the understanding of how our reality is what it is and what is really behind the reality we each perceive. So it is fantastic to hear such a knowledgable and eeply thinking expert give us a feel for both of these related goals. I would have liked to hear a bit more about quantum computing and whether the author feels that gives credence to the many worlds theory or not. The theoretical physicist and significant contributor to the Many Worlds Theory, David Deutch, posed the relevant question suppoting the Many Worlds Theory: how can quantum computers physically do the amount of calculation they do within the time they do, (i.e., if not for the input from other worlds - or at least reality from outside of our universe)? A mere 300 or so qubit quantum computer, when developed at some stage in the future, would have greater calculation power than a normal non-quantum computer using all the matter in our own single universe to make its calculations. To me Deutche's question seems like the smoking gun that gives the Many World theory enough to have it be the leading theory of quantum mechanics - but I may have missed something here?. Although my view of the reality of the Many World theory appears to be very slighly different to the authors (because i follow Deutch's slant on it a bit more), I found this book to be very well-paced, very well articulated and incredibly thought-provoking.