The proposed book maintains that schools face distinct types of challenges requiring distinct types of leadership. There are not, however, an infinite number of types of challenges, at least not for practical purposes. The book focuses on four sets of challenges that any principal might confront, depending on local circumstances. A principal can address each set of challenges successfully, but only by recognizing the distinctive nature of the challenges and adjusting his/her approach accordingly. This recognition of the need to make adjustments in leadership is referred to as differentiated leadership.The idea of differentiated leadership has its roots in contingency theory, situational leadership theory, and path-goal theory (Northouse, 2007). That the concept of leadership requires differentiation is further evidenced by the variety of adjectives used to modify the term instructional leadership, moral leadership, distributed leadership, servant leadership, normative leadership, and so on. In recent years, educators have been attracted to the notion of differentiated instruction. They have recognized that one form of instruction is unlikely to address the needs of all students. The approach begins with actual situations confronting contemporary principals and then analyzes the kinds of leadership functions most likely to handle the situations effectively. The book opens with an introduction to the idea of differentiated leadership and why it is important for principals to understand how different schools may face very distinct sets of challenges. Trying to apply a one-size-fits-all type of leadership can have disastrous results. The introduction also contains an overview of organizational diagnostics and the kinds of data needed to assess the particular kinds of challenges presented by a particular school at a particular point in time.