Just go and read Neil Shubin's essay over on John Brockman’s Edge site.
The take-home message of this essay is a simple one: The transition of animals from water to land in the Devonian period, 370 million years ago, was profoundly important in one sense and entirely trivial in another. It had a major impact on our world, but it did not involve any unusual or extraordinary biological processes. The effects of the transition are all around us. We see them in the rocks. We see them in ponds and seas around the world. We even see them when we shake hands. Let me explain.
It is well written (as one would expect of anyone associated with Brockman), has a great sense of history (not so common in science), and offers an insight into how and why scientists work and think the way they do. I’m eagerly awaiting the book it is excerpted from.
Thanks, Luigi, for the pointer.