Management theory dates back hundreds of years. It seems to have started at the beginning of the 19th century, with the emergence of the industrial revolution. There are four main areas that management theories tend to follow. These basic theories can be classified into classical, human relations, system and contingency theories. More recently, contingency theory has become popular (Mullins, 1999). Contingency theory is similar to situational theory in that it posits that there is no one answer to management. No simple or correct method in all situations. Situational theory focuses on leader behaviors with given situational factors (ChangingMinds.Org, 2010). Contingency theory takes a broad view, including contingent factors regarding the leader's ability and the situation. Contingency theories also argue that a leadership style that is effective in some situations may not be successful in others. In other words, the optimal leadership style depends on various internal and external constraints. These constraints may include: the size of the company, how it adapts to its situation, differences between resources and operational activities, management assumptions regarding employees, strategies, technologies used. Contingency Theory of Leadership The function of various contingencies in the form of subordinates, of the leader's success depends on task and group variables. The effectiveness of a given pattern of leader behavior may depend on the demands imposed by the situation. Different organizational situations may require these theories to be appropriate. No contingency theory has emerged as a universally accepted style. org/disciplines/leadership/theories/contingency_theory.htmJohnson, L. and Phillips, B. (2003). Absolute honesty: build a company culture that values ​​direct speech and rewards integrity. New York: AMACOM. Retrieved July 3, 2010 from http://www.questia.com/PM.qst?a=o&d=113716534Mullins, LJ, (1999). Management and Organizational Behavior, 5th Edition, PitmanPublishing, London. Retrieved July 3, 2010 from www.swin.edu.au/lib/infogate/management.htmThomas, MA (2005). Leadership Gurus. London: Thorogood. Retrieved July 3, 2010 from http://www.questia.com/PM.qst?a=o&d=110179612Value BasedManagement.net. (2010). Influences of constraints on organizations; Contingency theory. Retrieved July 3, 2010 from http://www.valuebasedmanagement.net/methods_contingency_theory.html