In 500 pages the author makes a full rotation of the subject since historical times. After his bestseller "The Elegant Universe" which is unrivaled, it is in my opinion one of the few relatively complete and detailed books written recently on the subject (it goes far beyond the work of John Barrow "the book of universe "yet already interesting).
This book require at least the tank level and be able to differentiate between a particle and a field of relativity and quantum, entropy and information symmetry and supersymmetry, although Greene made the effort to remain non-mathematical and expounds thus quite well.
If the first half of the book addresses the general public curious, we must recognize that the second part including a few paragraphs deserve a second reading to be well understood, even by experienced players.
It is true that the subject is complex and difficult and that everything back to basic and essential concepts is not always easy or even a good thing to have a clear idea but complete and precise the subject.
Greene has a very easy to read style but for my taste too prosaic and sometimes makes analogies to real-world situations in which an informed reader would be okay. This is perfect for the TV but I find this unnecessary lengths in a technical connotation book.
However, it uses the correct technical terms that fit the subject and as his bestseller The Elegant Universe, it is as easy to read quun Hawking.
You just have to understand that it comes to speculative theory and that Greene does not confront the theory to the existing or concurrent (LQG, etc.) and therefore not self-critical.
Translation also feels that is not literal, textual, and some twists on French have removed what was the specificity of the English text. This bravo for the translator because it is a long and difficult work in this field.
The hidden reality is more verbose and more superficial than lUnivers elegant, more in the style Trinh Xuan Thuan. But the air of nothing it contains still many concepts and 3 pages of bibliography and en uk.
NB. It is best to start with the reality hidden and once quon understood that, we can move on to Lunivers elegant, but it is a detail because the two books have much in common.
PS. Greene insists on string theory but also gives an overview of multiple universes, although it feels that this is not his cup of tea. Yet the concept is known as string theory which he smérites the sale.
Multiple universes or multi-verses are a hot topic since quantum physics and probabilities exist; if one believes some theories that have emerged there over 50 years (including that of Hugh Everett in 1957), nothing prevents there being more than 3 space dimensions or multiple universes.
Hartle Gell-Mann, Witten and others were passionate about these topics and Greene deepened their ideas from a mathematical point of view, the only one that can lead to a model of reality offering solutions or predictive results that astronomers and physicists will try to verify in situ.
If we correctly interpret the results of this work, our universe hitherto considered the sole ultimately would be only "interesting phenomenon" appeared spontaneously among other bubble universes like Brian Greene said.
These concepts represent a paradigm shift as important as the discoveries of Copernicus, Newton and Einstein.
It is through their effects quite unexpected that these ideas still seem revolutionary and even the responsibility of metaphysics even downright scandalous and irrelevant in the minds of some physicists and theorists who are wondering what can be the benefit of s 'interest in a subject as speculative and without any evidence.
Indeed the existence of multiple universes, like ropes or excess dimensions of the universe is revolutionary and sometimes disturbing. But it is not because an object or phenomenon is invisible it does not exist. Viruses, waves, atoms, quantum effects exist and we all benefit on a daily basis.
Similarly, one day, it may be that we can explore and take advantage of this hidden reality that is worth exploring.
In any case, it is by standing on the hill we can enjoy the real beauty of the 3rd dimension of an apparently flat world. If we continue in this direction and explore the multiple universe theory, a royal road may open to a new understanding of the world.
To read without moderation
See Also Brian Greene videos on the net, PBS (in UK) and Youtube (in vf).