Chapter 9 of a revised volume on school leadership, this chapter focuses on the principal's instructional leadership goals and functions. Leading the instructional program requires both an understanding of educational technique and a personal vision of academic excellence that can be translated into effective classroom strategies. Research shows that principals can have a profound indirect effect on students' learning experiences. This influence is shaped by the community and institutional context and by the principal's management style and personal temperament. Of the many tasks performed by principals, five most clearly influence a school's instructional program: (1) defining the school mission; (2) managing the curriculum and instruction; (3) promoting a positive learning climate; (4) observing and giving feedback to teachers; and (5) assessing the instructional program. Principals' instructional leadership duties should not be overemphasized at the expense of unofficial leadership found in schools. The key to effective instructional leadership may well lie in principals' flexibility in sharing duties and their ingenuity at matching these duties with the appropriate department heads, assistant principals, or teacher committees. Understanding the critical leadership functions is a good first step toward creating an effective learning environment. (MLH)