I recently finished reading Why Does E=mc²? (And Why Should We Care?) by Brian Cox and Jeff Forshaw.  The book has a very direct goal: explain why energy equals mass times the universal speed limit squared, and why it matters to us.  The authors take an approach that only mildly boarders on the classical way of teaching science.  While they do discuss relevant scientists and history as you would find in a science class, they only do so in a limited fashion and only when they need to show the previously-existing information and concepts that Albert Einstein stood upon to derive his famous equation, and then general relativity.  The style of the book is somewhat easy to follow, and is aimed at presenting the path to E=mc² to a layman without diving to far into math.

Cox and Forshaw used Pythagoras to arrive at the famous equation, which I have seen done before.  However, they take the time to spell out the argument, showing why the specific mathematical path is chosen.  For example, the Euclidean (flat-space geometry) version of Pythagoras is h² = a² + b².  The authors show why this version cannot be used because of causality (the flow of time), and graphical show why the non-Euclidean h² = a² – b² must be used instead.  From there they proceed, step by step, to derive E=mc².

This drive towards Einstein’s most famous equation takes the first half of the book, and for the most part the authors take a slow, steady approach.  But at the critical juncture when many abstract concepts such as spacetime, and vectors in space and time are being split, the procedure seems rushed.  In just a couple of page they throw away the cautious, explanatory approach and introduce new mathematical terms which are not immediately obvious.  They are not nearly verbose enough about the steps being taken, or about why new equations are being introduced.  I really felt I was reading a 5-star book up until this point.  I would use the analogy of going on vacation by flying to a tropical destination on a luxury private jet, then having to unload your own baggage from the plane when you got there.  I really wished the authors had spent at least another page or two explaining the final pieces.  But they didn’t and I had to reread the last section several times, and even consulted Wikipedia to try and figure out the mathematical tricks they were using.

The rest of the book dove off into the world of general relativity and quantum mechanics.  This was a good overview, but I real felt like the book went downhill after E=mc² was derived.  One big problem I had with the sections on quantum mechanics was the introduction of a “master equations”, which relates the various types of particles and forces at the elementary particle level.  Instead of reprinting the equation occasionally when discussing it, and perhaps highlighting the portions being discussed, the book simply referred to the one place it was printed.  This was very inconvenient and I finally got tired of going back to the equation again and again, switching between pages trying to follow along.  I would imagine that if the equation has simply been reprint 5 or 10 times where being discussed, with relevant portions highlighted, that the book would have gained a page or two.  That seems a small price for clarity on a very difficult subject.

What saved this book for me was the clarity of writing by the authors, and their obvious love of the subject.  I would like to find a better work on the subject to recommend to a layman, but this is still probably the best treatment I have read on E=mc².  Perhaps a second edition can make these editorial changes to improve the book. But if you are not concerned with every single mathematical step to the equation, then this is probably the book for you.

How did we get here?  This is one of the most important questions every asked, and is a cornerstone of religion, philosophy and science.  Of those three, science is the only one with a hope of answering the question.  To that end, Physicists Stephen Hawking and Leonard Mlodinow spell out their working theory in The Grand Design.  The title is ironic, as the authors quickly dispel the notion that there is a design or a designer.

Hawking and Mlodinow take us through a journey of scientific discovery, starting with the ancient Greeks and ending with modern physicists.  Slowly they build their case for a universe based on the theories of quantum physics and general relativity.  The book is surprisingly accessible, despite this rich subject matter.  Having read several other books on physics I was surprised at how little math was brought into play.  I think a true layman could probably get through this book and understand most of it.  You may pick up on some of the subtler points if you have a background in science or if you have read up on the subject.

The authors paint a picture based on the multiverse interpretation of quantum physics to explain our history (or histories!) going back to the big bang, or a bang-like event.  Its not novel per-se, as this approach has been discussed in the physics community in general.  But it does take on an interesting life with two prominent physicists explaining the theory.  Can we build an ultimate, theory of everything that helps explain how we got here by marrying quantum physics and general relativity?

I had the luck of picking this book up on a long travel day, and so I actually have the bragging rights of having finished a Stephen Hawking book in one day.  However, this probably included around 12 hours of reading, and the fact I finished it so quickly really speaks to the quality of the book and the level at which it is written more than my reading comprehension or intelligence!

I would recommend The Grand Design to anyone interested in our existence and how we got here.