How should rulers rule? What is the nature of power? These questions had already been asked when Niccolo Machiavelli wrote The Prince in 1513. But what made his thinking on the topic different was his ability to interpret evidence: to look at old issues and find new meaning within them. Many of Machiavelli's contemporaries thought that God would make sure morality was rewarded. To these people, it was inevitable that ethical individuals would enjoy success in this world and attain paradise in the next. Machiavelli was not so sure. He used the evidence of history to prove that people who...