Leadership is one of the most salient aspects of the organizational context. However, defining leadership has been challenging. The following sections discuss several important aspects of leadership including a description of what leadership is and a description of several popular theories and styles of leadership. This page also dives into topics such as the role of emotions and vision, as well leadership effectiveness and performance. 

Finally, this page discusses leadership in different contexts, how it may differ from related concepts (i.e., management), and some critiques that have been raised about leadership.

http://en.wikipedia.org/wiki/Leadership