Having read many books on quantum physics, with varying degrees of understanding on my part, including some which questioned the Copenhagen interpretation, I was quite amazed at the clarity of this volume, and learned a lot from it. It isn't a detailed explanation of quantum physics, assuming a basic knowledge on the part of the reader. This book is basically a very detailed explanation of why the author believes that Copenhagen is such an inadequate explanation, even though it seems to work. The author's belief is that an underlying principle still waits to be discovered, and I tend to agree. He makes a very good case, and this book is well worth reading.

There are three interwoven themes in this book. First, a history of quantum mechanics. Second, a description of a set of experiments with fluids which lead to a hydrodynamic quantum analogue (HQA). Thirdly, a description and critique of the many interpretations of quantum mechanics and the debate about whether there is or is not a more fundamental theory. Is quantum mechanics a statistical approximation of an underlying classical theory just as thermodynamics is a statistical approximation of classical mechanics? The dominant view, the Copenhagen Interpretation of Bohr et al, is that QM is complete. The opposing view, of Einstein and others, is that it is not.The history is first class. Kay presents detail that I have not come across in many other accounts and his the quality of his research into primary sources is exceptional. His exposition of Bohr’s work, de Broglie’s insights, Einstein’s comments, Bohm’s approach, etc. etc. is most illuminating.I can’t be enthusiastic about HQA. It may well be a useful classical model of a pilot wave (Bohmian) theory of QM. It may be sufficiently intriguing to catch the attention of professional physicists, in which case it has served a useful purpose.The critique of interpretations such as Copenhagen, many worlds, Heisenberg’s approach, is clearly heartfelt but remains, for the most part, objective. It is devastating. What is most unexpected is his questioning of the probability methods which provide the basis for Bell’s theorem and the refutation of hidden value theories. If he is correct then all bets are off and Einstein’s intuition may yet be shown to be right.The book is long, often repetitive, and not a casual read. Nevertheless it does deserve attention.

Excellent text. The book presents the concept of Hydrodynamic Quantum Analogs (HQA)—classical systems that appear to exhibit properties once thought to be hallmarks of quantum mechanics, such as superposition of states and tunneling effects. Armed with these experimental results, the author delves deeply into our way of understanding reality itself.The book also presents a terse but pointed criticism of the Copenhagen Interpretation of Quantum Mechanics. A firm realist, the author offers a strong case for Pilot-Wave Theory, the interpretation of quantum mechanics developed by David Bohm, building on ideas originally proposed by Louis de Broglie in the early 1920s.This realism-versus-anti-realism debate lies at the heart of our struggle to understand what quantum mechanics really means. Quantum mechanics is, operationally, a perfect predictive tool (so far). It can be relied upon to provide the best available predictions for future measurements of quantum states. But to believe that it describes the nano-world as such, one must give up the notion of an independent reality—and for me, that’s a step too far.In my opinion, what’s lacking now are new experimental results. At some level, the linear world of quantum states will have to give rise to the nonlinear world of classical physics. Until we have (or perhaps never have) such results, speculation remains our only option.And speaking of new experiments: since the problem seems to be one of scale, quantum computing—with its goal of entangling millions of qubits—may become the most consequential experiment in decades.Who knows? Perhaps from the labs of some startup, a new "Michelson–Morley" experiment will emerge, ushering in a new era of physics on our shores.

It’s annoying how so many reviews of this book seem to miss the point of the book. Have the reviewers actually read every page? I suspect too many of them have skipped pages assuming what was not there.I’ve read it all from cover to cover and let me tell you it’s a terrific book.Here are three key punches that will knock you back:1. Extensive science history showing parallels of the mistakes some of the sharpest minds in philosophy and physics are making today.2. Compelling arguments undermining the claims that there are any valid proofs that quantum mechanics is complete. ( the Copenhagen interpretation has no legs of proof )3. The book does not claim that reality is deterministic, nor does it claim that it is non-causal —- the major point of the book is that there is currently no valid reason to stop looking for underlying mechanisms that model and give insight into what our statistical models of QM currently surface.There is nothing irrational or weak that I read in the pages of this book. Bravo to the author. Terrific presentation.

I really enjoyed the sections telling about the history of scientific ideas and the people who developed them. His own theory is cogently explained, backed up by experiments and analogies. It makes me believe that there will come a time when the reality that underlies the probabilities of quantum mecanics.