Numerous explanations, classifications, theories and definitions about leadership, exist in the contemporary literature. Substantial effort has gone in to classify and clarify different dimensions of active leadership thus, generating considerable organizational and social research of leadership styles and behaviors. Many researchers and practitioners have developed a consensus that the progression of thinking over the years has developed a belief that leadership is a flexible developmental process, with each new piece of research building on and seldom completely disregarding that which was derived before it. Main theories that emerged during 20th century include: the Great Man theory, Trait theory, Process leadership theory, Style and Behavioral theory, Transformational, Transactional and Laissez Faire leadership theory
