From the author of The God Delusion, Richard Dawkins' The Blind Watchmaker has been acclaimed as the most influential work on evolution in the last hundred years. In 1802 the Rev. William Paley's argued in Natural Theology that just as finding a watch would lead you to conclude that a watchmaker must exist, the complexity of living organisms proves that a Creator exists. Not so, says Richard Dawkins, and in this brilliant and controversial book, the acclaimed evolutionary biologist sets out to demonstrate that the theory of evolution by natural selection - the unconscious, automatic, blind yet essentially non-random process discovered by Charles Darwin - is the only answer to the biggest question of all: why do we exist? 'I want to persuade the reader, not just that the Darwinian world-view happens to be true, but that it is the only known theory that could, in principle, solve the mystery of our existence' To Dawkins, The Blind Watchmaker is nature itself, gradually forming order from the very building-blocks of life: DNA. 'This might just be the most important evolution book since Darwin' John Gribbin 'Richard Dawkins has updated evolution ... his subject is nothing less than the meaning of life' The Times 'Enchantingly witty and persusive ... pleasurably intelligible to the scientifically illiterate' Observer Richard Dawkins is a Fellow of both the Royal Society and the Royal Society of Literature, and Vice President of the British Humanist Association. He was first catapulted to fame with The Selfish Gene, which he followed with a string of bestselling books: The Extended Phenotype, The Blind Watchmaker, River Out of Eden, Unweaving the Rainbow, and an impassioned defence of atheism, The God Delusion.
"The Blind Watchmaker" is very much a companion to "Climbing Mount Improbable". Both seek to explain how Darwin's theory of natural selection can explain what appears to highly improbably complexity in nature. "Watchmaker" is particularly insistent that not only does natural selection explain it, it's the only explanation that we have.
In the current climate, with opponents of science becoming ever more-vocal, the book retains its power in explaining key parts of evolutionary theory, and simultaneously debunking any alternatives and refuting common criticisms.
It starts by demonstrating quite what is improbable and complex about nature, using the sonar of bats as an example of a system that appears so well-refined as to be the product of design. Chapters go on to discuss the accumulation and selection of small changes in the genome, the role of DNA in replication, the possible origins of life and sexual selection.
Attacks on alternative theories include a detailed commentary on Eldredge and Gould's "punctuationism", disputes in taxonomy, and everything from Lamarckism to creationism. Sometimes there's a sense that Dawkins is fighting battles with scientific colleagues that would be better left to the specialist reader, but personally I found these squabbles helped illuminate the wider subject.
There's very little here on the evidence that evolution has occurred, whether from genetics or palaeontology. "Watchmaker's" territory is to explain how it has occurred, and why only natural selection can explain the complexity of life.
Evolution a process
(a) characterised by random mutation and/or replication of genes [individual]
(b) followed by cumulative selection of individuals based on interaction with environment [individual & population]
(c) effecting incremental changes over time [individual & population]
(d) and resulting in complex natural phenomena suited to survival / self-replication, bearing the illusion of design.
Dawkins defines life as adaptive complexity (the eye his typical referent); omits all reference to sentience, consciousness, homeostasis, purposefulness. "Living organisms exist for the benefit of DNA rather than the other way around" -- notes genes are effectually permanent while bodies exist but a generation.  "[T]he long-lived gene as an evolutionary unit is not any particular physical structure but the textual archival information that is copied down the generations. This textual replicator has a distributed existence. It is widely distributed in space among different individuals, and widely distributed in time across generations." 
Evolution the sole extant theory capable in principle of accounting for origin of life from non-living beginnings; validity wholly independent of deities or design.  Dawkins here unconcerned with the evidence supporting the theory, though instances are mentioned to illustrate points throughout. His aim is to clarify the theory and dismantle straw men arguments, such as that evolution creates complexity by "random chance", or random means anything can happen, or mutation responsible for adaptations in a single-step process, or that evolution is teleological.
Elements of Evolutionary Process
● Reproduction doubly-determined by (a) replication (copying genetic code, with or without mutation, into a new cell and destined for a new body), and (b) development or embryology (epigenesis: reading out genetic instructions to form a mature body)
● Survival defined as an organism's body preserving itself over time, and reproducing, with no comment whatsoever on what (else) may occur in that time. "Survival of the fittest" applies specifically to fitness to defend a body's physical integrity. An individual could endure a lifetime of despair, hunger, pain, fear -- and still be deemed "fit" or to have "succeeded" in life so long as progeny result. Conversely, an individual may have adapted beautifully to environment, having enjoyed a pleasant and productive lifetime but without progeny, and so considered "fit" or to have "succeeded" but not to have "survived". It is the genetic code which survives, not the bodily engine replicating that code.
● Adaptation is one of two things: (a) organism displays improved capacity for self-replication; (b) organism has greater chance for living longer, thereby indirectly improving capacity for self-replication. Presumably some adaptations would be undesirable for sentient individuals, at least in principle: do not confuse this definition of adaptation with better (i.e. an organism living a better life, however defined) though the overlap is great.
● Implies bodily attributes directly affect an organism's survival; and those bodily attributes are defined by genes (whether replicated or mutated). Put another way: progeny must resemble parents more than others in species, and selection must sort on that physical resemblance. Accounts for marginal improvement even of piecemeal evolution: the "pieces" of an eyeball are useful even before the full eye is developed, justifying the process of cumulative selection.
● Cumulative selection involves both selection (filtering in favour of specific features) and a cumulative effect (involving geometric progression as a feature becomes more widely distributed through a population over time as their competition is filtered out, and/or because certain genes replicate faster than others and account for a greater share of the gene pool in a population)
● Sufficient time for the necessary changes to occur: Dawkins posits thousands of millions of generations to human ancestry.
● Evolution may be "additive" and not merely "subtractive", noting that mutation, co-adapted genotypes, and arms races (in which genes / species co-evolve, being crucial aspects of one another's environments contributing to the selection process) all contribute to novel developments in evolutionary process, doing more than merely winnowing down from a given set of options.
● Dawkins claims cumulative selection favours continuous variables over discrete variables; also notes that digital / coded information is likely requisite. Interestingly, there also appears requisite a digital / analogue bridge in order to translate the digital archive into a physical form, which Dawkins describes as centred in the shape of proteins used to encode digital information.
● Simple action of a sieve / analogy with genes and proteins (physical shape determines interactions with environment determines output or pattern). Dawkins notes the human brain isn't wired to readily estimate evolutionary time scales nor the likely effects over that many generations. Notes we've evolved imaginations / sense of plausibility fit to our embodied existence, with human scale in the middle of our range of size estimates, and lifespan the midpoint of our time estimates. Outside of that we should rely on calculation not subjective judgment. [160-62]
● Sexual reproduction speeds evolution compared to asexual reproduction.
● Species vs Individual (characteristics, survival, adaptation); crucial dynamic is that evolution manifests at both levels, though strictly speaking only individuals are affected by genes.
● Dawkins postulates life originated just once on the planet, or at least there was one origin linked to all extant living beings today. (Progeny of other origins may have gone extinct.)  If true, gaps in the fossil record are requisite to identifying species, for elsewise every creature could be put on a spectrum rather than in discrete buckets. It's possible life originated more than once, so not all living things are related; but very unlikely given carbon-based life we've found. Silicon-basis is also possible based upon similarities between carbon and silicon; we've not found it. (I thought plant life was nitrogen-based: a branch from carbon-based roots?)
● Dawkins does not address the dynamics introduced by dominant / recessive genes; but touches on the vital step-process of DNA / RNA.
● Lamarckism combines (a) use / disuse principle with (b) inheritance of acquired characteristics, with (a) proven and (b) can never be proven false, can only be refuted by lack of observation of a positive instance. Yet, genes do not provide a blueprint of a mature body, rather a recipe for building a body as defined at birth, and genes are not read-write but read-only, so no capacity for capturing the newly acquired traits into the recipe. [296-98]
● Outlines four basic taxonomies relevant to biological evolution: phyleticists (cladists & traditional) and 'Pure Resemblance Measurers' (pheneticists & transformed cladists). Evolutionary tree the only true cladistic taxonomy with "zero" overlaps or "miscellanous" entries to exhaustively catalogue all possible entries, because branches in evolutionary biology always diverge, and never merge.
● Reminiscent of Bateson: Dawkins invokes St Matthews Gospel in his account of runaway feedback. "Unto those ..."
● Interestingly, William Bateson (Gregory's father) was an avowed mutationist.
● Dawkins originated the concept of meme in The Selfish Gene
Further reading ...
Dawkins, The Extended Phenotype
RA Fischer and neo-Darwinism e.g. Red Queen Phenomenon (?)
Egbert Leigh e.g. altruism & Green Beard Effect
Russell Lande and the phenomenon of carrying a physical feature (e.g. peacock plumage) and the preference for it (peahen attraction to said plumage) on the same gene, effect of which is to reinforce the dis/advantage of a feature
Originally published in 1985 and badly dated because of this (e.g. he’s oh so proud of his 64k computer) Dawkins is on his hobby horse of arguing against the creationists. I’ve read much better books on “why evolution is true” and this book dragged especially in later chapters. In addition Dawkins authorial voice is pompous and extremely patronising to those that don’t understand or question the validity of Darwin’s theory. OK creationists have got things wrong, young Earth creationists very badly so and they deserve a little derision but Dawkins argues with perhaps too much stridency and is therefore preaching to the converted. In addition Dawkins sometimes isn’t very clear in his explanations and even on a few subjects I thought I knew well I got confused by his explanation.
Overall – Evolution deserves a less pompous advocate, there are better books about evolution out there
One of creationism's arguments is that mutations for stuff like eyeballs wouldn't happen - it's too complicated for one mutation to make. And it couldn't have evolved piece by piece because the individual pieces are useless without the whole system.
Dawkins explains how things like eyeballs did evolve piece by piece by mutation, and how each individual step along the way was a useful mutation for the species as a whole.