[mrodock]

Explain to me why? Why will memorizing anything make you a better teacher to any student on any subject?

I've had teachers who knew their material so well they didn't even need a book for class and i have had others who needed the book in their hands in class during lecture. Neither imo was better than the other because one had a better memory.

I would be hard pressed to believe that the teachers that required a book in order to efficiently lead a class did not have much of the information memorized.

"Learning is remembering" (Plato). The thing is, it all goes back to remembering. Whether one thinks memorizing the book is useful or being able to recall instantly changes you have made with students and what approaches you took and how they worked. No matter, any discipline requires being able to remember what you need, when you need it. So too, remembering where you can find the information is very useful too, and can often be good enough.