Instructional leadership is the principal's role in providing direction, resources, and support to teachers and students for the improvement of teaching and learning in the school. This handbook reviews factors affecting that role in four broad domains: keeping informed about trends, planning for instructional improvement, implementing instructional improvements, and evaluating program success. The first section surveys the range of information with which principals must be familiar in order to provide knowledgeable guidance, including trends in instruction in specific content areas, trends in organization and staffing, and trends in media and methods. The second section discusses the application of planning techniques to instructional development, touching on needs assessment, goal-setting, standards and competency measurement, and obtaining support. Program implementation is covered in the third section, which explores program organization and the supervision of classroom management, the diagnostic process, student placement, and instructional practices. The final section treats the elements of the evaluation process, including assessment and reporting of progress, evaluation of teacher performance, obtaining and using community feedback, and modifying the program. (PGD)