Warren Gamaliel Bennis is an American scholar, organizational consultant and author, widely regarded as a pioneer of the contemporary field of Leadership Studies. Bennis is University Professor and Distinguished Professor of Business Administration and Founding Chairman of The Leadership Institute at the University of Southern California. 
“His work at MIT in the 1960s on group behavior foreshadowed -- and helped bring about -- today's headlong plunge into less hierarchical, more democratic and adaptive institutions, private and public,” management expert Tom Peters wrote in 1993 in the foreword to Bennis’ An Invented Life: Reflections on Leadership and Change.
Management expert James O’Toole, in a 2005 issue of Compass, published by Harvard University’s John F. Kennedy School of Government, claimed that Bennis developed “an interest in a then-nonexistent field that he would ultimately make his own -- leadership -- with the publication of his ‘Revisionist Theory of Leadership’ in Harvard Business Review in 1961.” O’Toole observed that Bennis challenged the prevailing wisdom by showing that humanistic, democratic-style leaders better suited to dealing with the complexity and change that characterize the leadership environment