I thoroughly enjoyed Richard Dawkins' book, The Blind Watchmaker. I read this right after reading Dawkins' earlier creation, the Selfish Gene. This book is brilliantly written and most importantly it conveys subtle and profound scientific ideas in easy and enjoyable language.
Some of the key concepts that Dawkins puts forward (which I was impressed with) include arguments for non blended, "particulate" inheritance and how this relates to sex. Also, he describes how one sees in sexual selection an unusual positive feedback, leading to such things as apparently inefficient long tails, and this is contrasted with the usual negative feedback that one tends to see in nature. The positive feedback loop results from the linkage between preference genes and the trait genes themselves.
There was a very nice discussion of genes and the environment and how the environment of genes includes other genes both within an individual and in other organisms, and this, in turn, leads to complex types of cooperation, arms races and the famous red queen effect. Finally, I liked the discussion of sensory systems such as vision and bat echolocation and how we can learn from these areas where nature has adapted to such a great degree and how we can see that in this process using less refined systems sometimes is evolutionarily advantageous.
Overall I found this a thoroughly enjoyable read and I would highly recommend it to anybody else. It is a great classic.
The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe without Design
by Richard Dawkins