This paper develops a working definition of teacher engagement, a definition based upon an understanding of how underlying assumptions about the goals of teaching affect what and whom teachers are engaged with, as well as how researchers' conceptions of proper power and authority in the school context influence what they see. Different dimensions of teaching that commonly remain in separate research traditions as discrete sets of teacher behaviors are integrated, e.g., teacher decision-making, classroom mangement, and curricular innovations. A number of assumptions guide this exploration of engagement among teachers. It is assumed that there is no one best way to be an engaged teacher, and a number of conceptions of teaching and learning are examined. The main body of the paper focuses upon the definition and interaction of the three main components--teachers, students, and the curriculum. Salient features of the secondary school milieu are examined and the conception of teacher, students, and curriculum are examined in four different images of education: discipline-centered, process-oriented, technical, and holistic. (JD)