Alfred Russel Wallace, c. 1895

©AMNH Special Collections

The letter delivered to Down House in June 1858 was as shocking as a thunderclap. Sent by the young naturalist Alfred Russel Wallace, it outlined a theory of evolution by natural selection eerily like Darwin's own. Wallace even cited the passage of Malthus that Darwin had cited in his notebook nearly 20 years before. Darwin was distraught: After all the years of work and worry, someone else would get the credit. He hated being scooped--and he hated himself for caring

Title page of the Origin of Species

But Darwin's friends, botanist Joseph Hooker and geologist Charles Lyell, sprang into action. They knew Darwin had written an essay containing those ideas nearly 15 years ago, so clearly he had developed the theory first. In a burst of energetic networking, Hooker and Lyell arranged a compromise: Wallace and Darwin would both have papers on the theory presented at the Linnean Society in London. Wallace was satisfied, and Darwin--finally--decided to get his theory into print without further delay. In little more than a year, he would publish his greatest book, On the Origin of Species by Means of Natural Selection.