Stephen has written ten books on the history of exploration, science, and ideas--including books on the medical mystery of scurvy, the Treaty or Tordesillas, the lives of Captain George Vancouver and of Roald Amundsen and a doomed Russian sea voyage. His books have been published in multiple English-speaking territories, translated into nine languages and shortlisted for many awards. Dennis interviews him about his newest book Dominion, about the transconinental railroad.