On November 24, 1859, the first edition of Charles Darwin's On the Origin of Species by Means of Natural Selection hit the shelves. It sold out the very same day (coincidentally, if anyone has a copy they are looking to get rid of I'd happily find it a good home). Since then, countless editions with countless introductions, forwards, and reviews have been published. You can get an illustrated version, a version bound with the other great works of Darwin, even a free electronic version for your electronic reading device. I'm sure when Darwin wrote of "endless forms" he had no idea he would be, in a way, referring to editions of his work. In fact, I'm sure that thought was far from his mind, being the modest individual he was. Rather, he was probably referring to something more like this:
This diagram of the branching tree (original by Charles Darwin, photo taken by Alexei Kouprianov, from Wikimedia Commons) is the only illustration present in the first edition of On the Origin of Species. Darwin used it to show the divergence of species from a common ancestor into the "endless forms most beautiful and most wonderful" that he saw in the world around him. This theory of evolution is simultaneously one of the most elegantly simple, and furiously complex notions in the history of science. But it is also one of the cornerstones of modern biology. So get your hands on a copy of "The Origin"* today or check out The Complete Work of Charles Darwin Online, and find out what all of the hullabaloo is about. I assure you, you won't be sorry. Happy Origin Day everyone!
*Just DO NOT get this one, EVER. Seriously!