Though written around 1513, more than 500 years ago, Italian diplomat Niccolò Machiavelli’s The Prince is still both widely read and very influential. Readers turn to it for its direct advice on the question of how to attain—and retain—power. Machiavelli’s answer, in brief: use any means necessary to make sure the state survives.

Given the changeable nature of politics, the strong ruler that Machiavelli describes may need to lie or cheat, deceive and, if necessary, resort to acts of violence—all the while maintaining an “image” of goodness. With enough skill—along with luck and favorable circumstances—the prince will retain his power.

Machiavelli’s ideas continue to be used today, by leaders both scrupulous and unscrupulous. Rightly or wrongly, his name remains a byword for political behavior that deals in realities rather than theories, making The Prince arguably one of the most influential books in the Western tradition.