Abstract
A personal recollection of Ralph M. Stogdill is presented, and the contribution of the OS U Leadership Studies to the understanding of leader behavior is reviewed with respect to the intermediate phase between the leader-trait and situational approaches to leadership. Together with the use of critical incidents and peer nominations, these studies formed the context for developing a transactional approach to leader-follower relations. This newer approach stresses the two-way influence and social exchange processes involved in leadership, with an emphasis on the two factors of system progress and equity. The results of research applying the transactional approach are summarized, with especial attention to leadership effectiveness.