This brief treatise on political doctrine, written by Niccolò di Bernardo dei Machiavelli (Machiavelli) in 1513, is the obligatory reference for every ruler faced with the demanding challenges of the res publica. This doctrinal for rulers, full of common sense and pragmatism, tries to teach how to acquire, maintain and strengthen a principality - city or region. The text, outside of any moral assumption, is a succession of warnings and advice to maintain the regency of the territory.