"Nothing in Biology Makes Sense Except in the Light of Evolution"
This phrase began as the title of an essay by geneticist and evolutionary biologist Theodosius Dobzhansky, and has become a maxim, a quotable quote. The short essay was published in 1973, in volume 35 of the journal American Biology Teacher. It was brilliant and cogent when first written, and still is in 2010. It remains a short, clear summary of the evidence that is overwhelmingly supportive of Evolution. It is essential reading for anyone interested in the Evolution-Creationism debate. Wikipedia has a summary of the essay, as well as an entry on Dobzhansky. PBS.org maintains a transcription of the article. Some libraries will have the back issue from 1973, and if your library subscribes, you can find a copy on JSTOR online. PDF copies can be found on the web, one of them here.