Despite the quote from Marcus du Sautoy on the front referring to this book by astrophysics professor Pedro Ferreira as a ‘guide to the outer reaches of the universe’, this is far more a book about what goes on in human brains – and specifically the development and partial solutions of Einstein’s general theory of relativity, which turned our understanding of the nature of gravitation upside down. For me it’s a three bears porridge book. We start off with a section that’s just right, then get a bit that’s far too long and end with a bit that’s far too short. (Okay, I know, the porridge was about temperature, not length, but this wasn’t supposed to be taken literally.) That ‘just right’ opening section gives us Einstein’s work and specifically the development of his masterpiece, the ‘perfect theory’, the general theory of relativity. This takes a totally opposite approach to, say, Cox and Forshaw’s The Quantum Universe . Where that book does not shy away from presenting difficul