The Conscious Mind
In Part I, Foundations, Chalmers describes the concept of supervenience and describes what he means by consciousness, which for the author is the subjective component of experience (the "hard problem"), as distinct from perception and pattern recognition of sensory input (the "easy problem" - or perhaps more accurately, "someone else's problem"). Perhaps an even harder problem is convincing people that there is a fundamental problem to be solved. The multiplicity of phenomena attached to the label 'consciousness' over the years makes this problem more difficult for Chalmers, who occasionally even seems to get confused himself, and frequently gets distracted.
In Part II, the main ideas are presented. The author tries to prove his main thesis, that consciousness cannot be reduced to material processes, using various arguments. This can not have been easy, given the difficulties defining the concept of consciousness in Part I. Five arguments are made:
Although the arguments seem to be mostly logically invalid or at best unconvincing, the author plows forward, building on the belief that consciousness is not reducible to simpler physical phenomena. If this point could be firmly established, it would be a discovery with profound implications; but the arguments put forward are not precise or compelling enough to convince many readers. "Reductionism" is also apparently a derogatory term for Chalmers, and he spends a lot of time criticizing the reductionist approach.
The author bases the remainder of the book on the conclusion, based on the arguments in Part II, that consciousness is "naturally" but not "logically" supervenient to any physical phenomena. Needless to say, this conclusion that consciousness is unexplainable leads the author into a property-dualistic philosophy, in which conscious experience is considered to be totally distinct from brain activity.
Part III describes the author's ideas toward a theory of consciousness. This section, like Part I, gets a little verbose, for example by belaboring at great length the minor question of whether "consciousness" and "awareness" are the same. Chalmers does not actually develop any sort of theory in the scientific sense, but mainly discusses what other philosophers have said on the subject, and then engages in unrestrained speculation, using arguments by analogy and intuitive judgments to determine their plausibility, on topics such as possible connections between information flow and consciousness. For instance, Chalmers asks whether thermostats might possess a rudimentary consciousness because of their information processing capability. This is a fascinating question, but considering the current impossibility of actually measuring consciousness or any other subjective phenomenon, wild speculation is about all that can be done at this point. One is left with the feeling that something more radical, fundamental, and unconventional is needed.
Part IV, 'Applications' discusses the author's speculations and thoughts on artificial intelligence and quantum mechanics. This is the most interesting part of the book, and gives an overview in very general terms of why some physicists think QM may shed light on consciousness, unfortunately without describing any of the actual experiments that lead them to this conclusion.
The main contribution of this book is its argument that a phenomenon of consciousness exists that is currently neither understood by science nor explainable by any current theory or conceptual framework. Many people, including at times, the author of this book, tend to get 'consciousness' confused with 'perception' and other cognitive phenomena. It is a fuzzy, slippery word. Much (or maybe all) of what people call 'consciousness' is an artificial construct invented by the brain to explain its own actions. Chalmers is one of the few authors to realize that the more difficult problem of explaining subjectivity is not addressed by neurophysiology, anatomy, or biochemistry. Indeed, he is compelled to spend much of the book arguing this point, as there are many influential people out there who do not believe it (Dennett, for example). Unfortunately, this leaves little energy or space for actually developing a coherent theory, and it is perhaps not surprising that the uncertain basis described above does not lead very far toward a theory of consciousness.
Finally, a minor problem is that the book is also full of politically-correct "she"s and "her"s. Now that most writers are finally settling on the use of "they" for a 3rd person singular gender-indeterminate personal pronoun, the continued use of the feminists' P.C. style only detracts from the book's readability.