In a now-famous Harvard Business Review article first published in 1990, John Kotter suggested that a clear distinction be made between leadership and management. In his opinion, both are essential but fundamentally different. A manager deals with the complexity organizations entail; a leader directs the change. In both action systems, one must decide what needs to be done, create networks of individuals and relationships that permit the implementation, then ensure that these people are actually doing the work. But in practice, these three tasks are carried out in completely different ways.