Think of it!" says Peter Raven, the director of the Missouri Botanical Garden, as he stands beside a table in the rare-book room of the garden's library and reads aloud from the final paragraph of Darwin's Origin of Species. "All that difference, elaborately constructed, produced by laws!"

Then he rereads the entire paragraph, which gives one chills, partly for Darwin's understatement. What the author deemed "interesting to contemplate" was nothing less than the world's biological structure, which he (and others) had discovered, and which now, at the end of his monumental study, he quietly celebrated in sublime summation. The "tangled bank" he had initially attributed to an unnamed power, but in the third and subsequent editions, he included God in the evolutionary process. The book now ends on this glorious sentence, over which Raven exults: "There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved."