Wonderful Life: The Burgess Shale and the Nature of History by Stephen Jay Gould
a great read!
This is mine as well. Much of the conclusions as to the nature of the organisms discussed were overturned not too long after the initial publication, but what he says about the misinterpretations of Darwin's theory and the mechanism of evolution is really good stuff -- as well as the copius illustrations.
led me to Gould and is also nicely done.