Rating: 
Summary: Not enough consideration of the experimental situation...
Review: There is great excitement currently about quantum computing and its laboratory realization. Recent press releases have indicated successes in implementing quantum computation and this no doubt has encouraged the excitement. The authors of this book have been directly involved in the experimental and theoretical developments behind quantum computing and have written a fair summary of the subject as was known at the time it was first published (2000). The theory behind quantum computing is outlined in some detail in the book, but the experimental situation is not, and this is disappointing since it is the laboratory realization of quantum computing that is most interesting. Most implementations of quantum computing theoretically are dependent on the notion of entanglement of states, and in my opinion there is no convincing experimental evidence of entanglement. Theoretical constructions that employ entanglement have grown considerably in recent years, but the experimental situation is far behind these developments. This book unfortunately does not look critically at the experimental justification for entanglement, but uses concepts of entanglement throughout to lay the groundwork for a theory of quantum computation. Indeed one could say that the entire book rests on the notion of entangled states and being able to manipulate these states via various transformations, called 'entanglement transformations' by the authors. The authors do however devote an entire chapter to the physical realization of quantum computers , although again no real experimental data is given. The role of the decoherence time is emphasized in the discussion, and a chart is given listing rough estimates for decoherence times for various candidate realizations of quantum computers. Several different scenarios for quantum computers are outlined in the chapter, and the discussion gives some credence to the view that the theory of quantum computation has some physical meaning to it, rather than just a theory of computation based on the properties and geometry of Hilbert space. Indeed, one could easily take this later viewpoint, as it is one thing to call a mathematical construction 'quantum' and another to really find a physical (quantum) system that actually behaves in a manner compatible with these constructions. If one is to speak of 'quantum' computation and not just 'Hilbert space' computation, one must show beyond doubt that the system executing the computation is indeed a physical and quantum one. A mere statement that 'physics is computation' is not enough. Indeed, there are a few examples of using Hilbert space properties to enhance the performance of various algorithms. For example, one can speed up the training portion in neural networks by complexifying the weights. In addition, one can employ a tunneling scheme to alleviate the problems of local minima in these networks, and in gradient algorithms in general. These approaches all take advantage of Hilbert space geometry and the ability to do superposition of states, but none of them correspond at all to physical systems, let alone quantum ones. They are merely mathematical tools used to speed up (dramatically in some cases) a particular algorithm. There has also been a great deal of very exciting research in the employment of the 'quantum' point of view in pure mathematics. New methodologies have been developed for handling difficult mathematical results using such a viewpoint and these have resulted in brilliant developments, especially in differential topology and algebraic geometry. The chapter on distance measures for quantum information in this book could be viewed as part of these developments and strategies. The definition of the fidelity between two quantum states is purely a mathematical convenience that is used (albeit productively) to derive quantities that behave as one would want them to (viewing from a classical standpoint). No physical relevance is given for this metric in the chapter, although it is interesting from a mathematical standpoint. The authors are honest to admit this though, for they state that notions of quantum information are in a state of infancy and no solid (physical) definitions have been given as of yet. If more time were spent on the analysis of the raw experimental data behind the efforts to build quantum computers, and less on purely theoretical considerations, this book would have been a lot more helpful. The literature is bursting with papers on entanglement and its relation to quantum computing and quantum information, but unfortunately, not enough critical analysis of the experimental situation. This book is no different in this regard, but the authors are still enthusiastic about the prospects for quantum computing, difficult as they are. One can only hope that their efforts are successful, that such machines will be built soon, as the consequences are awesome.......
Rating: 
Summary: The Reader Review by Julian Miller is INCORRECT!
Review: This book covers quantum information theory at a level that can be understood by someone who has only had an introductory course in quantum mechanics and the same in basic computability theory. While this still rules out most of the general public, this is an excellent book for anyone seriously thinking of entering the field. The first third of the book reviews the required basics of quantum mechanics, computability, and information theory, and outlines where QIT differs from the classical theory. The rest of the book goes into more specifics.
While this book does cover introductory level quantum circuit design, elementary quantum information theory, and the basics of just about every part of the field, it doesn't go into terribly much depth. This makes it an excellent introductory book (targeted at graduate or upper-level undergraduate physics majors), but if you want something more targeted towards a particular facet of quantum computation and information, you may want to try something else.
Rating:
Summary: Good, just advanced enough
Review: This book covers quantum information theory at a level that can be understood by someone who has only had an introductory course in quantum mechanics and the same in basic computability theory. While this still rules out most of the general public, this is an excellent book for anyone seriously thinking of entering the field. The first third of the book reviews the required basics of quantum mechanics, computability, and information theory, and outlines where QIT differs from the classical theory. The rest of the book goes into more specifics.
While this book does cover introductory level quantum circuit design, elementary quantum information theory, and the basics of just about every part of the field, it doesn't go into terribly much depth. This makes it an excellent introductory book (targeted at graduate or upper-level undergraduate physics majors), but if you want something more targeted towards a particular facet of quantum computation and information, you may want to try something else.
Rating: 
Summary: Could be better
Review: This book has a lot of potential, but unfortunately many passages are very unclear and appear hastily written. This isn't a surprise since apparently one of the authors of the book obtained his Ph.D. immediately before the book was written. Also background material and definitions are put together poorly, so its unlikely one could use this book in a self-contained fashion. For example the definition of big-o notation is really poor, and seems like the authors scribbled it on a piece of paper in a hurry and then typed it in their manuscript. After this lousy definition there are problems asking you to show this or that is big-o of such and such but there are no examples showing you how to do this beforehand. Engineers and computer scientists will probably have to go elsewhere for background in quantum mechanics while physicists will have to look elsewhere for background in theoretical computer science. The book contains tons of exercises (upwards of 70 or so in a chapter), but no solutions or examples. Many discussions are simply unclear. A reader might compare Preskills online notes for better thought out explanations. I think that the overall organization of the book could serve as a basis of a more in depth and better thought out rewrite. I would suggest cutting back significantly on the number of exercises and providing examples and at least some solutions of the problems. If the book is going to put in background material, it should be more in depth and instructive. Provide a detailed example on how to perform a certain type of calculation or analysis before throwing a bunch of exercises at the reader. The tone of the book should also be modified somewhat. Yes, the field is exciting but they overdo it with explanation points after too many sentences. The book is currently enjoying a high position since this is a new field and there isn't much competition. But my bet is that in the next few years better books will hit the scene.
Rating:
Summary: Great reference text - hard to learn from for the first time
Review: This book has found its many uses as a reference. In particular the citations helped me locate key papers that I needed to work toward my research project. If you want to do research in this area than I recommend you add this text to your collection without question, however if you are trying to teach yourself quantum mechanics (like I did) I can suggest several other books that will help you along your quest.
This book lacks worked examples, I recommend the worked problems text: (Problems & Solutions in Quantum Computing & Quantum Information, ISBN: 9812387900) This book also skips over many `simple' concepts as expected for the depth of coverage. The kindest introduction to quantum computing out of the dozen books on my shelf is:
(Approaching Quantum Computing, Dan C. Marinescu, Gabriela M. Marinescu , ISBN: 013145224X).
There are now many texts on the subject of quantum computing, but there is a reason why this text is citied hundreds of times by the top people in this field. For a research project you must get this book, if you are teaching a class it might be wise to mention this book and refer students to another text. I think that the text (Explorations in Quantum Computing, ISBN: 038794768X) is good in the amount of material covered, but does not go into depth on key points -- It could be argued that the Mathematica simulation files more than compensate for this. I have not had a chance to read the Gruska text (Quantum Computing, ISBN: 0077095030) since it is out of print for the time being. I hear a new addition is on its way and I am interested in reading that book.
I would say that this text will remain a classic but the material is not easy for me to grasp. The book is hard, but quantum computing is hard so this is expected. I could live without the other texts on my shelf, but I need NC. If you do buy this book search for the "Quantum Computing Tutorial by Mark Oskin", an Assistant Professor at the University of Washington. His notes were designed as a guide for his students using the NC text, and they will help you get through some key examples. I downloaded the file: quantum-notes.pdf but it is also free in latex for professors.
Rating: 
Summary: Book is too long for such a young field
Review: This book is about 700 pages long. That fact alone speaks volumes about it. For me a good physics book is one that unifies a subject and clearly highlights those ideas which are most important. Less important ideas are relegated to exercises or left out altogether. For an example of a brilliant, almost ideal book on a closely related subject, see the book by Cover and Thomas on Classical Information theory. The Nielsen Chuang book is so disappointing by comparison. It does very little unifying and almost no filtering. Its authors are content to mention everything they've ever heard about (a mad effort to impress us?). A kind of saturation bombing, with the hope of hitting a target whose identity they are not sure about. If you are going to read 700 pages, you would do much better to compile a list of the 50 most important papers in the field of quantum information. Then go to the Los Alamos eprint library and read them. At an average of 15 pages per paper, you would end up reading 750 pages and you would, in my opinion, learn infinitely more, since learning from 50 highly original minds is better than learning from two not very original ones. Has this book been battle tested in a classroom? I doubt it, since neither of its authors is a teacher. If the book had been tested in a classroom before rushing to press, maybe some of the problems that I've mentioned about lack of unity and filtering would have been fixed.
Rating:
Summary: Excellent introduction and guide
Review: This book is not only a thorough and gentle introduction to quantum computing and information; it is also a great reference I keep at my desk at all times. The book reminds me of a guide book; if you get lost or aren't sure of or don't know something, all you need to do is open this guidebook.
It's difficult to critisize this book because any weaknesses I've encountered so far seem to me like oppurtunities to learn new things. If something is unclear, it is easy to pinpoint what needs clarification and what to seek help for to understand the topic. The book doesn't throw random, useless or complicated notation at the reader. All of that is explained clearly and simply.
For readers looking for experimental developments, this book does contain a section on a few techniques known by 2001. However, it is important to remember that this book is an introduction to the processes of quantum computing and not so much the implementations. The chapter on implementations serves as a nice way to give the reader an idea of what's been realized so far.
I recommend this book to anyone interested in learning about quantum computation and information, as well as those working in the field.
Rating:
Summary: It is still hot from the authors.
Review: This book is probably grow from the Ph.D thesis of one of the authors. Personally I benifit very much from this book. Quantum computing and quantum information (science- the authors don't want this word) grow too fast these years. Nobody have complete knowledge of all that is required. Because of the expanding speed, no one (working in this field) have time to write a book. It indeed need a Ph.D student's work to make it. This book fill up some of my missing knowledge to understand the literature. The authors' concise and clear explaination for some idea make the reader easy to enter this field. Perhaps because the authors were living in California or perhaps because they are somewhat young, some part of the book does not sounds like other bibles from the same publisher. I think it will be better when the second edition come out (but at that time the book will probably lost many other attractive points.) For me the length is o.k. It indeed need so many space to cover such a broad topic. However, the retail price is somewhat too high.
Rating:
Summary: Holy, Schroedinger's cat batman!
Review: This book rocks. This is an excellent introduction to the quantum information sciences. Its level is probably best suited for advanced undergrads or graduate students, and it is a handy reference for those researchers in this area of physics/computer science. My only real complaint is that the author insist that 'z' be pronounced 'zed' throughout the book. LOL.
Rating:
Summary: Essential Quantum Information/Computing
Review: This is *the* book to learn Quantum Information/Computation theory from. I tried others but nothing made much sense until I read and worked through this book, then I went back to the other books and everything made sense to me. Someone who has been doing research in this area for many years probably cannot use this book for much other than an occasional reference, but for those who want to learn the subject it is a GREAT place to start.
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