Machiavelli's best-known book, Il Principe, contains a number of maxims concerning politics, but rather than the more traditional subject of a hereditary prince, it concentrates on the possibility of a "new prince". To retain power, the hereditary prince must carefully maintain the sociopolitical institutions to which the people are accustomed; whereas a new prince has the more difficult task in ruling, since he must first stabilize his newfound power in order to build an enduring political structure. He asserted that social benefits of stability and security could be achieved in the face of moral corruption. Aside from that, Machiavelli believed that public and private morality had to be understood as two different things in order to rule well. As a result, a ruler must be concerned not only with reputation, but also must be positively willing to act immorally at the right times. As a political scientist, Machiavelli emphasized the occasional need for the methodical exercise of brute force or deceit.