Niccolò Machiavelli was an Italian diplomat, philosopher, and writer who lived during the Renaissance period. He is best known for his book, The Prince, which offers advice on political leadership and power. Machiavelli's ideas often emphasize the importance of pragmatism and realpolitik, suggesting that rulers may need to be cunning and ruthless to maintain their authority. Machiavelli's work has sparked much debate over the years, leading to the term "Machiavellian," which describes actions that are deceitful or manipulative. Despite the controversy, his insights into human nature and politics continue to influence modern political theory and discussions about ethics in leadership.