The capability to lead and influence people is essential for success even beyond management. Professionals without a formal leadership role find themselves more and more often in situations where it is key to deliberately influence people, teams, divisions or the whole organization. Thus despite – or perhaps precisely because of its great relevance, leadership is often seen as something mystic. This impression is reinforced by a large number of popular business bestsellers about leadership, CEO biographies, and executive consultants who rely on individual experiences and anecdotal evidence when writing and talking about leadership. These sources generally provide only a limited informative value and therefore are of questionable use for the development of leaders and professionals.