Modern scientific research on leadership in organizations has been evolving for nearly a century. Over the course of its development, four particular discourses of leadership have emerged: normative, interpretive, critical, and dialogical. This entry surveys major leadership theories and research within each discourse. It pays particular attention to ways in which the concept of communication has evolved and its role expanded from being a subsidiary component in normative, psychological theories to being a primary process in the leadership theories and research found in the other three lenses. The entry ends with several suggestions for the future growth of leadership studies.