Fred Fiedler was an American psychologist best known for his work in the field of leadership and organizational behavior. He developed the Contingency Theory of Leadership, which suggests that a leader's effectiveness depends on the situation and the specific context in which they operate. This theory emphasizes that there is no one-size-fits-all approach to leadership. Fiedler's research included the creation of the Least Preferred Co-worker (LPC) scale, a tool used to assess a leader's style by evaluating their feelings toward the person they least enjoy working with. His contributions have significantly influenced how organizations understand leadership dynamics and improve team performance.