Deeper than I expected and quite to hard to follow the descriptions of Penrose diagrams and what one would see whilst tipping into a Black Hole. Enjoyable never the less, and I am now intrigued to read the authors prior book; why E=Mc2. Last few chapters give a good explanation of the more recent ideas around holographic equivalence and the conservation of information in a black hole. I especially liked the last chapter on quantum information redundancy and the link with quantum computing, even if I didn't understand much of it! ( )

Excellent and exhaustive book entertainingly written. If you’re not good at maths I would avoid it. A lot of geometry and algebra, a little calculus. ( )

Black Holes: The Key to Understanding the Universe, written by Brian Cox and Jeff Forshaw, is an excellent introduction that falls into an area of popular science books that can be misleading.

Let me first talk about the broad area of popular science books. This is not, as some people treat it, a single level of science texts, but a spectrum from very basic to something that still requires effort but is not academic. The difficulty is that often books that require some effort and perhaps some familiarity with mathematics gets lumped in with academic books. If we are going to say that academic books are definitely not popular, or that there is no overlap, then we have to be open to shades of popular books. This is, as far as I'm concerned, a popular science book but one that requires some effort and, for a deeper understanding, some math background.

Since I am not an astrophysicist and my last classroom experience with advanced mathematics was a couple of decades ago, I consider myself a layperson with respect to this topic. So I am approaching this book as popular science. My preference, since I have done some reading in the area and taken a few MOOCs on the topic, is for a more rather than less challenging popular science book. If, for whatever reason, you want a challenge and not simply a less nuanced super-basic introduction, this is the book for you.

I found the explanations and examples/analogies to be very effective in discussing the concepts. The analyses using the formulas were, with some effort on my part, very helpful as well, though admittedly some remained just beyond my grasp (for now). I will also say that I think this is one of those books that can be read without too much close attention paid to the math. What I mean is that while the explanations centered on math certainly offer the opportunity for better understanding, they can be skimmed, and the concepts still understood because of the wonderful explanations.

I would highly recommend this for those who are willing and want to put in the effort, or for those with some formal education in the area. My first introduction to relativity was with the Brehme diagram way back in 1976 and seeing how graphic representations have evolved was fascinating. For those who don't mind skimming the math in order to get to the conceptual explanations, this will be a good book for you. If you want a very basic, relatively math-free explanation and don't really care for any nuance, this might not be the one for you.

Reviewed from a copy made available by the publisher via NetGalley. ( )

Whether on stage, television or in a podcast, Brian Cox is one of the most approachable science popularisers alive today. And black holes remain some of the most alluring phenomena in astrophysics, which is why it's a surprise that Black Holes, a marriage of a subject that captures our imagination with an author usually so adept at firing our imagination, turned out to be a tough and overly-academic read.

It starts promisingly, with Cox positing that black holes are "cosmic Rosetta stones" (pg. 21) that give us many valuable – and unexpected – scientific insights. They are, the book's subtitle has it, "the key to understanding the universe", and after providing an overview of black hole research, from Einstein to Hawking, Cox leads us deeper into the rabbit hole with discussions of worldlines, the 'Kerr wonderland', quantum gravity and the idea of the universe as a hologram.

Leads us, but soon leaves us behind. I recently attended one of Brian Cox's Horizons Live lectures in Manchester (which I reviewed here), where Cox proved to be engaging and able to explain difficult concepts clearly to a general audience. He was also keen to impress a sense of wonder about the makeup of the universe. This, to my great surprise and dismay, wasn't really replicated in Black Holes, even though the topic was much the same. This book, co-written with Jeff Forshaw, one of Cox's colleagues at the University of Manchester, reads for the most part like a dry textbook for undergraduates. It is packed full of diagrams (moving far beyond the Penrose diagram which Cox utilised in his live show), graphs and equations of rapidly increasing complexity.

Now, as a general rule, whenever someone produces a graph I reach for my revolver, but I imagine even those readers who are more inclined to jump through the various mathematical hurdles Cox and Forshaw erect will find them a bit excessive. I once read a popular science book (The Universe in Your Hand by Christophe Galfard) which gamely introduced the reader to all the wonders of then-contemporary astrophysics with the promise that only one equation (Einstein's famous E=mc2) was needed in order to understand it. Black Holes doesn't do this – not even close – and my eyes began to glaze over every time a new equation was introduced and then explained in a dense and academic series of paragraphs without much in the way of respite.

Very well, you might say – what did you expect? And certainly I didn't go into Cox's book expecting an easy time of it. The topic is an intense and difficult one, even before you get to the cutting-edge stuff which the authors discuss in the final chapters. And yet, it did feel like a textbook, like there might be an exam waiting at the end. "It is worth checking that you understand the diagram well enough… before you read on," Cox writes on page 59. If I had, I might well still be on page 59. I have read – and mostly understood – a fair chunk of popular science in my time, and found this book severely wanting when it came to popular science's most important task: bringing the reader along.

It's a great shame, because the cutting-edge ideas delivered, however imperfectly, in the book are fascinating and profound. The 'Rosetta stone' analogy proves apt, as the authors show that a study of black holes leads us to a greater understanding of the makeup of the universe and the nature of spacetime, gravity and reality itself. This is why, the authors argue at the end of the book, "it is vital that we continue to support the most esoteric scientific endeavours", because no one could have predicted that we would find such links in studying black holes (pg. 263).

It's a fair point, but the book itself doesn't do enough to bring those esoteric ideas into the minds of the mainstream reader, and the impact of this profound discussion is consequently diminished. In the Horizons Live show I attended, Cox joked about performing an 'equation solo' in the arena (which is usually reserved for musical acts), but Black Holes' equations are less a blistering thirty-second solo of astonishing impact and more like those indulgent twenty-minute soloes where you wish the guitarist would bring it home and we can get back to the song itself. Too often, I was left wondering who Cox and Forshaw believed they were talking to in the book – surely they must have noticed many of their readers had fallen behind?

On page 210, the authors write that "there are electrons in your hand and electrons in the Andromeda Galaxy, separated by over 2 million light years, [but] linked through quantum entanglement". It's a good line, and the sort of thing that readers of popular science like myself lap up. But such lines are too rare in Black Holes, which too often forgets to invoke this sense of wonder. It's noteworthy that the page immediately following this line provides not one or two, but four equations. As a science book, I'm sure this must be a remarkable and accurate piece, but as a popular science book, it must be considered something of a failure. ( )