Darwin's Darkest Hour tells the remarkable story behind the unveiling of the most influential scientific theory of all time, Charles Darwin's theory of evolution by natural selection. Darwin spent years refining his ideas and penning what he called his "big book." Yet, daunted by looming conflict with the orthodox religious values of his day, he resisted publishing–until a letter from naturalist Alfred Wallace forced his hand. In 1858, Darwin learned that Wallace was ready to publish ideas very similar to his own. In a sickened panic, Darwin grasped his dilemma: To delay publishing any longer would be to condemn his greatest work to obscurity–the brilliant argument he had pieced together with clues from his voyage on the Beagle, his adventures in the Andes, the bizarre fossils of Patagonia, the finches and giant tortoises of the Galapagos, as well as the British countryside. But to come forward with his ideas risked the fury of the Church and perhaps a rift with his own devoted wife, Emma, who was a devout Christian.