common leadership approaches that work well in one set of circumstances but fall short in others. Why do these ap-proaches fail even when logic indicates they should prevail? The answer lies in a fundamental assumption of organiza-tional theory and practice: that a certain level of predictabil-ity and order exists in the world. This assumption, grounded in the Newtonian science that underlies scientifi c manage-ment, encourages simplifi cations that are useful in ordered circumstances. Circumstances change, however, and as they become more complex, the simplifi cations can fail. Good leadership is not a one-size-fi ts-all proposition.