The author challenges the role of knowledge in teaching by pointing out the variety of issues and concerns teachers must simultaneously address. Teachers use two strategies to manage their multidimensional space: They develop integrated habits and rules of thumb for handling situations as they arise, and they plan their lessons by envisioning them unfolding as a drama might. It is entirely unclear where or how knowledge enhances teachers' visions, but it is very clear that visions depend on a strong sense of purpose, direction, and momentum. Most teacher educators try to foster visions in their students, but their interest in vision creates two problems. First, it places them in conflict with their university brethren who expect to see them promulgating knowledge. Second, the particular vision they embrace is too narrowly progressive; it ignores many concerns that teachers try to juggle in their practice and many societal ideals for education as well.