"Evolving the Mind" is an excellent book about the material basis of consciousness from an unorthodox but thoroughly clear-headed and scientific point of view. The style is conversational, accessible, and entertaining. The discussion focuses on the essential concepts and questions, avoiding various philosophical "isms" (e.g. functionalism, dualism, etc.) that tend to inflame intellectual prejudices and cloud the real issues.
There are many recent books about scientific theories of consciousness (some very good), but frankly many of them are saying nearly the same thing: consciousness is to be identified or associated with some particular aspects of computation (e.g. planning, decision-making, self-representation, etc.) among neurons in the brain. In these theories, while random noise is understood to affect processes at the sub-cellular level, the brain at the functional level is assumed to operate as a deterministic computing machine. This assumption is present even in current sophisticated theories involving chaotic dynamics, parallel distributed processing, or feedback (a.k.a. "re-entrant connections").
Because Cairns-Smith's writing style is conversational, open-minded, and non-confrontational, some experts (e.g. neuroscientists, cognitive psychologists, computer scientists) are liable to miss the powerful challenge to mainstream approaches to a fundamental theory of consciousness running through his book. This main point has two parts. First, based on the correspondence between conscious experiences and evolutionary fitness (e.g. fire feels bad, food tastes good), consciousness must have evolved. If it evolved, that means (according to evolutionary theory) it must have some effect on the organism's physical body or behavior. Second, since in contemporary neuroscience models the dynamics of the brain are completely determined by the local "mechanical" action (by electro-chemical signals) of neurons, conscious feelings cannot have any effect on the brain's behavior. Various ways have been tried to wiggle out of this, but it's a real problem--conscious feelings aren't allowed to have any effects on the organism's structure or behavior, but that's inconsistent with their evolution by natural selection. As Cairns-Smith details, this problem was clearly spelled out by William James before the solution favored by Cairns-Smith, using 20th century physics, was even conceivable.
To arrive at his outline of a solution to his impasse, Cairns-Smith starts from a lovely historical introduction to relevant ideas from physics, chemistry and neurobiology. Another reviewer dismissed this approach as a mere bias due to Cairns-Smith's background in chemistry. That's an unfair conclusion, because Cairns-Smith builds a strong case that the physical composition of the brain, and not just its functional organization, is important for understanding consciousness. Ultimately Cairns-Smith proposes that large-scale quantum states may provide a substrate for consciousness in the brain together with a resolution to the problems faced by classical models. Again, another reviewer dismisses this as merely the latest in a line of "fad...metaphors" for the mind in terms of the latest technological device. I disagree; I don't think that reviewer fully engaged the arguments put forward in the book.
I somewhat agree with the reviewer who complained that the book lacked a conclusive final chapter. The last chapter is a dialogue between a proponent and a critic (said to be based on a conversation with Francis Crick) rather than a summary and conclusion. This is in line with the atmosphere of the book as a free inquiry into the possibilities, as opposed to a dogmatic adherence to a pre-determined conclusion. Also, the book ends just at the point where one would hope to find a detailed neurobiological model. That's probably as it should be, though, given the variety of possibilities and the lack of specific evidence. But again experts are liable to think that this openness and vagueness justifies their belief that the quantum mind hypothesis is implausible or already ruled out. (A technical example: many scientists consider that macroscopic quantum effects cannot occur at room temperature in the brain, a viewpoint buttressed with calculations by Tegmark. These calculations apply under equilibrium conditions, but not under conditions when energy is pumped into a system, such as the ATP energy continually pumped through biological cells. A rigorous model by Frohlich shows how the kind of quantum states proposed by Cairns-Smith can arise in biological tissue at room temperature. Cairns-Smith covers the Frohlich model, but does not bog down his discussion by emphasizing that the Frohlich model effectively answers the brain temperature objection.)
The reputation of quantum theories of consciousness often suffers from an association with new age philosophies or anti-scientific mystical attitudes. Among the more reputable proponents of a quantum mind model is Roger Penrose. However, the complexity and subtlety of his argument can leave his conclusions in doubt even for readers with an open mind and some relevant math, physics, or logic background. Like Penrose, Cairns-Smith never wavers from scientific rigor. This is especially remarkable since a major thrust of his book is to make a historical case for boldly imaginative thinking, highlighting the controversial additions of "spooky" concepts to the scientific world-view. Ultimately, testing the quantum mind hypothesis will require models that specify the interaction between putative quantum states and the well-established neural machinery of action potentials and synaptic transmission. "Evolving the Mind" provides an excellent background for evaluating such specific neurobiological models.
I highly recommend this book, whether to introduce the issues to a novice, or to loosen up an expert who thinks he already has it all figured out.