Many of the policy documents and much of the recent literature talk about "leadership" when discussing the role of headteachers and principals of schools. The word is also used when writing about other senior and middle managers. It is a way of showing the difference between what used to be expected of headteachers and what is expected of them now. They now have more responsibilities. As a result, they need different characteristics and a wider range of knowledge and skills. "Leadership" is a generic term. It opens up the possibility of learning from the exercise of successful leadership in other organisations, particularly where improved performance is needed. Leithwood and Strauss note it is "the major factor accounting for successful turnarounds". Leadership, particularly by the headteacher, is important in promoting school improvement. Research has also identified the role of middle leaders, particularly heads of subject departments, in shaping the academic effectiveness of the school. In this Review, for the sake of clarity, job titles such as "headteacher" and "principal" are used. This Review looks at key aspects of policy and practice relating to headteachers: their changing role; management of supply; recruitment; performance management; training and development. An annex presents: "Responsibilities of headteachers." [National Foundation for Educational Research (NFER) carried out the scoping and bibliographic work on which this review was based.]