Preface My father always told me that I would be a teacher. He didn’t mean it in a nice way. My father talked in riddles. As the only child in the house, I had plenty of time and opportunity to figure out what he was really saying. This was it: I am afraid that like me, the best you will be able to do in life is to be a civil service worker. He was also saying: If he had realized he was going to be a civil service worker, at least he could have been a teacher, which he might have enjoyed. He wasn’t really talking about me at all. I never had any intention of being a teacher. I didn’t particularly like school and later, when I became a professor, the part of the job I disliked the most was the teaching. One might wonder how I wound up being a professor if I disliked teaching, and one might wonder why Tam writing a book about teaching if I dislike teaching. One also might wonder whether I still dislike teaching. Yes. And no. It depends on what one means by teaching, which is, after all, what this book is about. The other day my 3-year-old grandson Milo told me he was going to teach me how to throw rocks. It seemed an odd idea. What could he mean by this? To Milo, “teach” means to tell someone what to do and how to do it and then have the person do it too. Teach is part of tell plus imitate for Milo. Milo is 3. It is not too surprising that this is what teach means to him. It is a little surprising that he thinks he should be his grandfather’s teacher, but that is another issue. But it is really no shock that Milo thinks this is what teach means. It is what nearly everyone thinks teach means. The commonly accepted usage of teach is tell and then have the person who was told, do what he was told. This certainly is not what teach ought to mean, or more important, is not what good teaching is. And, every good teacher knows this. The problem is that the system that employs teachers doesn’t know it and more or less insists that Milo’s definition be the one that is follow