I can heartily recommend Stephen J. Gould's excellent book on the Burgess Shale A Wonderful Life. By telling the story of the discovery, interpretation and then re-interpretation of the assemblage of oddballs and wonders of the Burgess Shale Gould explains the detail of how evolution and natural selection works as well as pointing out the very unlikely scenario we found ourselves in, in which a species of ape that developed the ability recognise it's own conciousness became very successful in a very short space of time (before fucking the planet up big style due to a spectacular lack of self-control).

Highly recommended.