I wrote about it in much more detail back in February, but today is the actual 150th anniversary of Charles Darwin's On the Origin of Species, which was first published on November 24, 1859. That was more than two decades after Darwin first formulated his ideas about evolution by natural selection.
Some have called The Origin the most important book ever written, though of course many would dispute that. It's certainly up there on the list, and unequivocally on top for the field of biology. Darwin, along with others like Galileo, radically changed our perceptions about our place in the universe.
But Darwin was a scientist, not an inventor: he discovered natural selection, but did not create it. We honour him for being smart and tenacious, for being the first to figure out the basic mechanism that generated the history of life, and for writing eloquently and persuasively about it. His big idea was right (even if it took more than 70 years to confirm), but some of his conjectures and mechanisms turned out to be wrong.
He was also, from all accounts, an exceedingly nice man. Among towering intellects and important personalities, that's pretty unusual too.