It is obvious that teaching is a very special art, sharing with only two other arts, agriculture and medicine, an exceptionally important characteristic A doctor may do many things for his patient, but in the final analysis, it is the patient himself who must get well, grow in health. The farmer does many things for his plants or animals, but in the final analysis, it is they that must grow in size and excellence. Similarly, although the teacher may help his student in many ways, it is the student himself who must do the learning. Knowledge must grow in his mind if learning is to take place.

p. 12 - How to Read a Book (1940, 1972)