"Hacking Matter" deserves 4-5 stars for addressing a very interesting topic - artificial atoms - and 3-4 stars for its presentation. The book can be divided into two parts. The first section, about 110 of the book's 200 pages, gives us a tour of actual research in solid-state physics and its implications for material science. The second launches us from real developments to speculative devices and applications. McCarthy tries to focus the book on programmable matter and only touches on other aspects of nanotechnology. I think that's a great idea, but it should have afforded him the opportunity for deeper explanations of research and ideas that were only briefly described.
McCarthy is facile with language, as might be expected from a writer of fiction. But while the reading flows easily, the first section suffers from an uneven handling of the material. For example, McCarthy delays the discussion of atomic orbitals until the middle of the book, and even then it's a watered-down introduction with the reader directed to a freshman chemistry textbook for more information. Given the complexity of the topic, I felt he should have assumed a certain level of reader compentency, start with a more detailed review of the atom with better diagrams of orbitals and material characteristics, then build from there and drop the "monkey on limbs" analogy. In contrast to some areas of hand-holding explanation, some quotes from physicists, given without further explanation, assume a certain level of sophistication from readers:
"In general, high temperatures tend to equal more interactions, because there are a lot more blackbody photons emitted from hot surfaces, which can then be absorbed and destroy atomic superpositions. But photon-photon interactions have such a low cross section you don't have to worry about it for optical quantum states. A photon that's in a quantum superposition is therefore going to be a lot more stable at room temperature." (p. 71)
Perhaps it's praise to McCarthy that I wanted more of the first 100 pages -- like a thorough introduction to atoms and how material properties arise, side-by-side diagrams of natural and artificial atoms in terms of scale, electron density plots, more details on the research, etc. It's fascinating stuff and there are references at the end of the book.
The speculative portion of the book, although it occasionally veers from the focus on programmable matter, is well-written and thought-provoking. McCarthy notes that the interviewed researchers are reluctant to speculate, and he steps into that void and presents some possibilities. One chapter describes a hypothetical construct for handling an array of quantum of dots: a "Wellstone Fiber" invented and submitted for a patent by McCarthy and his partner.
Back in the late 80s, K. Eric Drexler, referenced at least twice in "Hacking Matter," used his book "Engines of Creation" to speculate on possible directions for nanotechnology, well ahead of actual technical developments. While some of Drexler's ideas may not be realistic, he did galvanize interest in the subject. I can't help but think McCarthy is trying to play that role for artificial atoms and the funding of condensed matter physics research. For those of us who don't think that much about material science, this book provides a good wake-up call in the form of an entertaining read.