The exercises which teachers conduct in their classrooms do not commonly involve a single type of mental activity. It is true, however, that certain lessons tend to involve one type of activity predominantly. There are lessons which seek primarily to fix habits, others in which thinking of the inductive type is primarily involved, and still others in which deductive thinking or appreciation are the ends sought. As has already been indicated in the discussion of habit, thinking, and appreciation in the previous chapters, these types of mental activity are not to be thought of as separate and distinct. Habit formation may involve thinking. In a lesson predominantly inductive or deductive, some element of drill may enter, or appreciation may be sought with respect to some particular part of the situation presented. These different kinds of exercises, drills, thinking (inductive or deductive), and appreciation are fairly distinct psychological types. In addition to the psychological types of exercises mentioned above, exercises are conducted in the classroom which may be designated under the following heads: lecturing, the recitation lesson, examination and review lessons. In any one of these the mental process involved may be any of those mentioned above as belonging to the purely psychological types of lessons or a combination of any two or more of them. It has seemed worth while to treat briefly of both sorts of lesson types, and to discuss at some length, lecturing, about which there is considerable disagreement, and the additional topic of questioning, which is the means employed in all of these different types of classroom exercises. _The Inductive Lesson_. It has been common in the discussion of the inductive development lesson to classify the stages through which one passes from his recognition of a problem to his conclusion in five steps. These divisions have commonly been spoken of as (1) preparation; (2) presentation; (3)comparison and abstraction; (4) generalization; and (5) application. It has even been suggested that all lessons should conform to this order of procedure. From the discussions in the previous chapters, the reader will understand that such a formal method of procedure would not conform to what we know about mental activity and its normal exercise and development. There is some advantage, however, in thinking of the general order of procedure in the inductive lesson as outlined by these steps.