Want to know the difference between the Renaissance and present-day society? If Machiavelli had written The Prince today, it would be called Ruling Principalities for Dummies. In the fifteenth century, manuals for prospective rulers took the form of profound philosophical treatises. In the twenty-first century, they're bullet-point lists bound in bright yellow covers with a cartoon on the front. Part history and part philosophy, The Prince is a glimpse into the mind of a…