Book by RichardDawkins on principles of Evolution
Note that the second edition is substantially better than the first, and you should read the footnotes. Sometimes the main text says one thing and the footnotes completely contradict it.
And in those high and far off times, O Best Beloved, there was a scientist who liked to tell JustSoStories, about how the elephant, with 'satiable curiosity, got his long trunk, how the Glyptodon got its scaly armor, and how the Homo Sapiens got his ability to make shit up that sounds scientific...
My favourite book.
See Also: MemesShmemes