Nicolo Machiavelli was born in Florence, Italy in 1469. His famous treatise, The Prince focused on the political problems and power struggles a monarch might face while attempting to stay in power.
The tactics in The Prince, while initially aimed at preserving power in a monarchy, provide instruction for fledgeling evildoers and pragmatists everywhere. The central tenet of the book is that certain virtues, while praised by the masses, will only lead to downfall. On the other hand, vices that are commonly despised might lead to success. For example, if a leader appears generous, then he risks going broke in order to retain his reputation. Generosity is best done in secret, and a leader should appear stingy.
The most commonly quoted statement of Machiavellian tactics is that "It is better to be feared than loved." In general, people are ungrateful, cowards, greedy, and false, and cannot be relied upon. If one is feared, people will always keep that fear in mind. If one is loved, people will be a traitor to love when it is to their advantage.
Machiavellian tactics, much like those of Sun Tzu, often emphasize misdirection. He teaches that a leader must know how to be deceitful when it suits his purpose, but he must not appear that way. Because, while it is better to be feared than loved, the best way to avoid being overthrown is to avoid being hated. A Prince must know how to do wrong, and when to properly use this to his advantage, often in secret. Princes that use cunning are generally more successful than those that could be fully trusted.