Being fascinated by evolution and actively studying it, Darwin's On the Origin of Species by Means of Natural Selection is simply a must-listen. Remind yourself of the time at which Darwin published this book and it becomes even more astounding. I would not recommend this book for anyone who is curious about evolution and natural selection as this can get very dry, very quickly. I would try an abridged version if you don't want to hear every little detail about the book.
The narrator left a lot to be desired and seemed to have to force his way through the book and did not at least sound like there was an interest on his part in the subject matter.