Book excerpt: In this captivating double life, Adam Gopnik searches for the men behind the icons of emancipation and evolution. Born by cosmic coincidence on the same day in 1809 and separated by an ocean, Lincoln and Darwin coauthored our sense of history and our understanding of man’s place in the world. Here Gopnik reveals these two men as they really were: family men and social climbers, ambitious manipulators and courageous adventurers, grieving parents and brilliant scholars. Above all we see them as thinkers and writers, making and witnessing the great changes in thought that mark truly modern times.