School effectiveness as a field for study is a child of the 1960s. Although its origins lie in the West, some fine research is now to be found in the East. Like other aspects of that turbulent decade, school effectiveness has enjoyed an ‘interesting’ history. Since its earliest days the field has been riven by conflict on such issues as if, how far, and how, schools matter, and can be shown to matter, in determining levels of student achievement. A major subset of these general controversies has focused on if, how far, and how, school principals matter and can be shown to matter in determining levels of school effectiveness and student achievement. I will examine these, and related, themes and in so doing will consider if a knowledge of what makes schools effective helps in enabling a school to improve. This discussion will serve as a prelude to the next part of my chapter in which I will outline a three-level portrait-based approach for the study of school leaders and will illustrate its possibilities drawing on my twenty-five years of research into the life and career of the school principal.