This paper proposes a new way of thinking about teacher supervision that takes into account the everyday experience of the teacher in the classroom. The paper suggests eliminating old habits of thought by using new language with new connotations--instead of "supervision," the new approach is called "professional development." Professional development is one of three functions of "educational leadership," an activity in which all educators may be engaged to various degrees. The other two functions are curriculum development and organizational development. Professional development is divided in its turn into four components: staff development, including formal and informal methods for working with groups of teachers to achieve organizational goals; informal observations consisting of brief classroom visits improving the administrator's knowledge of teachers' activities, styles, and needs; formal rating processes providing specific information to be used for employment-related evaluation; and individual development, comprising processes used to help teachers meet personal, individual needs. The paper also suggests considering supervision as a craft, a science, and an art, all at once. All three of these aspects of supervision must be exercised if professional development efforts are to be thorough and effective. (PGD)