Leadership in view of Harold Koontz (1989) is influence, art, or the process of influencing people so that they will try to achieve the goal of the group with the willingness and enthusiasm. Agree with Harold, that lead is an act that requires the intelligence and expertise with 'touch' art.
The art of how to influence that people so enthusiastically trying to achieve a common goal. How to keep people meredusir personal interests, minimize sensitivity, and embracing diversity.
In line with Harold, F.I. Munson "The Management of Man" defines leadership as the ability / willingness to handle or work on people so as to achieve maximum results with sekecilnya possible friction and maximum (for possible) cooperation.
Influence others to cooperate based on the person's ability to lead others in achieving desired goals group.
(From various sources)