As many reviewers before me have said, this is a difficult, mind-boggling subject and it would take a great teacher to explain all these concepts to someone interested in popular science in a completely amateurish way. Unfortunately, the authors don't manage it. Despite various unnecessary sections, I've re-read this book hoping to understand why E=mc2 (I still don't understand why, nor why I should care, as the cover promises). I am not new to popular science - I loved Fabric of the Cosmos, Brief History of Time and User's Guide to the Universe so was not quite prepared for the frustrations that this book would kindle.
Firstly, it 'explains' the most basic maths operations in unnecessary detail (for example, the fact that forward slash means divide or Pythagoras's right angle theorem). Would anyone who does not know how to do basic division be reading a book like this? But then it glosses over the really difficult sections in just a couple of lines, so when you actually DO need an explanation you're just given loads of incomprehensible maths jargon without any indication whatsoever of how it actually works (for example, I didn't have a clue what the authors were on about when they brought up, out of the blue and without any reasons, a hyperbola in the Spacetime chapter). Or, sometimes, the authors don't even bother to explain and reassure the reader 'to take our word for it'.
Secondly, I felt a bit of exasperation being promised every day examples of science at work - especially when these 'examples of science in every day life' turn out to be a 2 page digression on the prophecies of Nostrodamus. After a humourous conclusion to Nostrodamus I still wait for the example from every day life. Of course, it never comes and the chapter concludes with the reader made fully aware that quantum physics is present in every sphere of his life but without a single useful example being provided. A lot of paper in this book seems wasted on such silly examples or unnecessary, patronising explanations of basic maths operations - but not enough on explanations of ideas that really require it, eg Planck's constant - absolutely awful and bewildering discussion of this concept.
The second part of the chapter on 'Spacetime' was equally unclear and patchy, going from having breakfast in your room, to an imaginary space shuttle, to a motorcyclist whizzing through spacetime, all the while including references to points on a hyperbola without a single mention of how or why the graph actually relates to reality... what does it mean if a point is moving along the hyperbola in spacetime terms??? I'd urge you to read Natural Laws of the Universe instead if you want a clear, succinct and lucid account of the laws of the universe. And to understand E=mc2, buy A Biography of the World's Most Famous Equation which does a far better job than Why does E=mc2. Simple language and not very mathematical, but at least it genuinely is aimed at non-physicists.