One thing I don’t understand about lectures is why the lecturer covers the material that is already presented in the book and assigned as reading material to the students.

Is the assumption that some students are actually incapable of reading? If not, what then is the point of covering the same stuff in the lecture? Imagine that reading the book is a lecture itself: what then is the point of giving two identical lectures?

I understand that some students may not understand the book, and a spoken lecture makes it possible to answer questions and provide clarifications on unclear statements from the book, or just to add more detail/intuition to a certain topic.

But, truth be told, those parts of a lecture make up a small, small minority. **Most** of the lecture is indeed spent on just repeating what the book said – except of course with much less detail, since you can’t cram 30 pages of written words in a 1 hour lecture.

So would it not be much more efficient to do it differently? Here’s one example for a 1 hour lecture, but you can think of your own:

- Spend the first 15 minutes on recitation of the book material. It gets everyone on board, sets the tone, refreshes everyone’s mind. During these 15 minutes, certain added remarks can be made if the lecturer feels them necessary.
- Spend the next 10 minutes answering questions by confused students.
- You now have 35 minutes left to cover
*extra material*not presented in the book. This could be in-depth examples or intuition of the topic just covered, advanced extensions, or just some extra topic that you wouldn’t have time to otherwise cover in your course.

This way you are both more efficient since you are not wasting time repeating stuff, and you also take care of students’ questions and get some time to add clarifying remarks. You get the best of both worlds.