On a memorable day in human history, February 12, 1809, two babies were born an ocean apart: Abraham Lincoln in a one-room Kentucky log cabin; Charles Darwin on an English country estate. It was a time of backward-seeming notions, when almost everyone still accepted the biblical account of creation as the literal truth and authoritarianism as the most natural and viable social order. But by the time both men died, the world had changed: ordinary people understood that life on earth was a story of continuous evolution, and the Civil War had proved that a democracy could fight for principles and endure. And with these signal insights much else had changed besides. Together, Darwin and Lincoln had become midwives to the spirit of a new world, a new kind of hope and faith. Searching for the men behind the icons of emancipation and evolution, Adam Gopnik shows us, in this captivating double life, Lincoln and Darwin as they really were: family men and social climbers; ambitious manipulators and courageous adventurers; the living husband, father, son, and student behind each myth. How do we reconcile Lincoln, the supremely good man we know, with the hardened commander who wittingly sent tens of thousands of young soldiers to certain death? Why did the relentlessly rational Darwin delay publishing his "Great Idea" for almost twenty years? How did inconsolable grief at the loss of a beloved child change each man? And what comfort could either find--for himself or for a society now possessed of a sadder, if wiser, understanding of our existence? Such human questions and their answers are the stuff of this book.