A major claim in this chapter is that the differences between high-effect and low-effect teachers are primarily related to die attitudes and expectations that teachers have when they decide on the key issues of teaching - that is, what to teach and at what level of difficulty, and their understandings of progress and of the effects of their teaching. It is some teachers doing some things with a certain attitude or belief System that truly makes the difference. This brings me to the first set of attributes that relate to Visible learning inside': passionate and inspired teachers.