I read this because Douglas Adams recommended it a number of times in Last Chance to See and elsewhere; and also as a follow-on from my earlier reading of Dawkins's The Selfish Gene and Charles Darwin's On the Origin of Species. Dawkins argues that natural selection is the blind watchmaker in nature. Animals and plants evolved when their genes mutated to create variations. The variations that benefited them (i.e. helped the gene to survive) were kept; the variations that made it harder to sustain life are discarded. But the timeline of evolution is on a different scale of magnitude to human time, so you have to put on your hiking boots of thought.
This book is accessible to a general audience, but I wasn't always wearing my hiking boots; sometimes I was in my slippers, so some of the biological nuances will have slipped me by. I think Dawkins is at his most readable when he's using analogies to explain complex natural processes. I was captivated, for example, in his description of how dust particles interact with streams to redirect its flow; or how DNA is more of a reciple than a blueprint; or how he created a computer program to mimic how biomorphs evolve.
He's at his worst when sneering at other schools of thought that he disagrees with or which have been scientifically disproved. He sounds like a bit of an arrogant snob. But one who's very good at what he does.
This audiobook version is narrated by both Richard Dawkins and Lalla Ward. In The Selfish Gene, the second narrator was used to read footnotes and asides, and I think that's also the function of the second voice in this book, but that was never spelled out. It gives the book a slightly uneven surface but also underlines that scientific discoveries are also evolving and need to be constantly revised and revisited. It's possible, also, that the Lalla Ward sections are revisions that were added after Dawkins's original recording. But an explanation would have been nice.
It remains remarkable to me (someone who never studied biology as a subject beyond some basic lessons in introductory science at secondary school) that Darwin's theory of evolution is so dominant: how often he is cited, expanded, and updated. He is the Shakespeare of his field.