The principle argument of the book is that information is the fundamental element that constitutes our universe - more fundamental than energy, or its condensed offspring, matter. While this is a large claim, the early part of the book is a delight: a simple and clear introduction to the basics of information theory, elaborated with easy-to-understand examples that only occasionally lead the reader mildly astray. The author outlines why the majority of information-bearing systems in nature tend to be digital (digital encoding requires less energy and is simpler to error-correct) but he ignores important exceptions (phenomenon such as pressure waves are analog).
Major problems with the author's argument soon appear, however. One problem is that Vedral accepts as axiomatic the notion that less common events convey greater amounts of information in consequence of the fact that they are less common. But a moment's reflection suggests that the story cannot be so simple. Less common events do not necessarily contain more information, nor do they necessarily require more information to describe them. Although the author illustrates his idea by talking about how common words are shorter and less common words are longer, it is merely a generalized tendency towards efficiency that has resulted in the inverse log-proportional distribution of word frequency/word length in many (but by no means all) languages. To see why infrequency per se does not imply greater information content, imagine that there is only one kind of car on Earth, but it can come in two colors: blue and red. Out of every ten cars made, nine are blue and one is red. We know therefore that our probability of seeing a red car is 1:10 but it would be absurd to argue that the red car intrinsically contains or represents more information than its blue counterparts. Thus a basic foundation of the author's argument is unsound, and so the reader needs to be somewhat skeptical about the logical structure that is erected thereafter.
Later in the book, Vedral goes on to state - without providing sufficient grounds - that disorder is actually information accumulation, and that entropy is equivalent to information saturation. Presumably the author means that organized systems become disorganized over time as a result of interacting with their environment, and so the disorder is a kind of record of that interaction. But the reader may have two objections. The first objection is that whatever connection is meant is not in fact stated, and the second objection is that if we are correct in guessing the author's intention (that disorder is a record of the system's past interactions with its environment) then the author has just twisted information theory right out of its socket. Information, if the word is to have any meaning, must mean a state that can be "read" to elicit knowledge of that state. Disorder - entropy - is essentially unreadable because it is a jumble of apparently random states. So when the author conflates entropy with information saturation, he seems to be making a very big - and very unjustified - leap. It is one thing to say that the maximum entropic value of a system is equivalent to its maximum information-carrying capacity, but quite another to claim that the two are therefore identical. Additionally, it is probably incorrect to make the claim that the maximum entropic value of a system is in fact equivalent to its maximum information-carrying capacity, because the vast majority of information-carrying systems require some inbuilt error-correcting system, which itself requires information elements (bits, in a binary system) that otherwise would be available for the "message" itself.
Things get worse. When the author moves on to discuss the issue of environmental change, he treats the Earth as though it were a closed system. Thus he accounts for energy conversion into heat, but totally forgets that the Earth radiates most of its heat into space. Instead of an intelligent discussion about the tremendous complexity of environmental systems, we get a schoolboy exegesis that is utterly facile and just silly, and which has nothing whatsoever to do with the central thesis of the book. Even worse comes when the author extrapolates across cosmic timescales. Due to the fact that the sun will end its life by expanding and destroying the inner planets (including our own) some five billion years from now, he concludes that our only hope is to move to other planets. A moment's reflection might indicate that no species we know of lasts for more than a few tens of millions of years so the possibility that anything even vaguely human would still inhabit the Earth five billion years hence is simply ludicrous. A better editor would have insisted on excising sections like this altogether. On the other hand, there are moments of unintentional humor, as when the author tries to talk about food in terms of its entropic value - here I was reminded strongly of Nabokov's novel Pale Fire, in which the insane narrator sees everything through the highly distorting lens of his personal minor obsession and thus "explains" external events in terms of his inner madness. Unfortunately for Vedral, I very much doubt this was the effect he was striving for.
This obsession with explaining absolutely everything in terms of one phenomenon (either entropy or information, depending on the page you happen to be on, as the two are conflated early on and never manage to separate again, like a pair of conjoined twins lacking the presence of a surgeon) basically is the reef upon which Decoding Reality founders. This obsession causes the author continuously to overlook some very basic and obvious problems with his "explanations." For example, he makes an analogy between betting and evolution. This is one of those school-room analogies that, like many analogies, can both shed light and cast shadow. In this case, alas, the latter wins out. The author ends up arguing that as life becomes more elaborate ("increases in entropy") it becomes more difficult for life to propagate. A quick glance out of the window shows this to be utter nonsense. Six hundred million years ago there was no animal life on Earth beyond that contained within the oceans; since then life has also colonized the land and there are literally millions of tiny ecosystems within which different species and sub-species can find a place. But according to Vedral, the opposite should be happening. Which means, of course, that Vedral is too busy paying attention to his idée fix and not spending enough time engaging with the world as it actually is. And that is a shame, because in those places where he is more focused and less expansive in his claims, he conveys ideas clearly and with interest. So all in all this is a curiosity of a book - intended as a thesis about information and reality but in fact being a record of one man's curious obsession through which everything is distorted. By the half-way point I was ready to toss the book into the nearest bin, but persevered in the (alas vain) hope that it would redeem itself at some point. So if you are a connoisseur of oddities and obsessions, this is very much the book for you. But if you are looking for a serious contribution to our knowledge of the universe, you won't find much of help within these pages.