Who decides what to do in the classroom?

As a child I put all my faith in my teacher. In first grade she made us co-writers of our textbook, and in second grade I just assumed she had written all the books during summer break. Later, I realised teachers often chose to use books written by other teachers, and later still I realise that the choice might not even be a real one. There are few books to choose from, they are not very different from eachother and factors such as price and local availability may be just as important as the teacher's preferences.

And as I am analyzing textbooks from an adult point of view, I am also aware that these books very often dictates classroom activity - especially if you are to use them with the teacher's manual.

I am afraid I will come out of this textbook analysis project with my faith in teachers totally crushed. But I plan to follow up by interviewing teachers, and hopefully they will restore my faith that most teachers are noe the teacher portraited in the teaching materials.