I highly recommend these four segments on BBC's In Our Time, which include some of the most insightful expert commentary (particularly segments 3 and 4) I've heard recently.
My favorite Darwin-related books are The Selfish Gene by Richard Dawkins and Darwin's Dangerous Idea by philosopher Daniel Dennett. Dennett writes
"Here, then, is Darwin's dangerous idea: the algorithmic level is the level that best accounts for... the diversity of species, and all of the other occasions for wonder in the world of nature. ...No matter how impressive the results of an algorithm, the underlying process always consists of nothing but a set of individually mindless steps succeeding each other without the help of any intelligent supervision." (p.59) ***
Now let me make a controversial remark in light of Dennett's observation. Because the true working of evolution is best understood as an algorithm (requiring, at least, some idea of a fitness landscape in a space of high dimensionality), a deep understanding is impossible without mathematical sophistication. See, Fisher, Hamilton, Haldane, Wright. The mindset of such people is often quite different from that of the typical biologist, who delights in diversity and detail as opposed to unifying principles and mathematical simplicity.
See the Darwin family tree for evidence of hereditary genius (Galton was Darwin's cousin and pioneered statistical ideas like correlation, regression and the normal distribution).
*** I'm quite sure Dennett appreciates that this comment can be applied to intelligence itself (AI) as well as to evolution ;-)