There's no doubt that Jim Baggott is one of the best popular science writers currently active. He specialises in taking really difficult topics and giving a more in-depth look at them than most of his peers. The majority of the time he achieves with a fluid writing style that remains easily readable, though inevitably there are some aspects that are difficult for the readers to get their heads around - and this is certainly true of his latest title Quantum Space , which takes on loop quantum gravity. As Baggott points out, you could easily think that string theory was the only game in town when it comes to the ultimate challenge in physics, finding a way to unify the currently incompatible general theory of relativity and quantum theory. Between them, these two behemoths of twentieth century physics underlie the vast bulk of physics very well - but they simply can't be put together. String theory (and its big brother M-theory, which as Baggott points out, is not actually