This treatise on politics was the fruit of Machiavelli's many years of experience as a diplomat and historian and circulated in 1513 but not published until 1532. It was dedicated to Lorenzo de Medici, a member of the ruling dynasty of Florence.

In Machiavelli's view the ideal ruler is an effective executive rather than a moral paragon. If one desires power, one must take all the appropriate steps to acquire and maintain it. As models of successful princes, Machiavelli offers the examples of Pope Alexander VI; his son, Cesare Borgia; and Ferdinand of Aragon - men who were able, energetic, persuasive and intimidating and always prepared to act unethically if it suited their purposes.

The essential immorality of Machiavelli's central premise - that in politics the end justifies the means - led to the book being banned by Pope Paul IV in 1559.The translator has appended two other works by Machiavelli that describe the modus operandi of an effective ruler: a description of the methods adopted by Cesare Borgia at Sinigaglia in 1502 in removing his enemies and a biography of Castruccio Castracani (1284-1328), the ruler of Lucca.