Just in general, when we look at our school system, there is so much overlap with our criminal justice system in terms of our low-income youth.

In North Carolina, for example, it takes 15 years to move a teacher's salary from $30,000 to $40,000. So it's really difficult to argue that pay doesn't have something to do with the lack of prestige.

This is something that Randi Weingarten said to me when I interviewed her once, which I think I quote in chapter nine. She talks about how only 7 percent of private sector workers in the American economy are in unions. So all the protections that teachers have that are due to collective bargaining - including generous pensions, generous health plans, limits to what they can be asked to do after school and in the summers - all of those things are sources of resentment to the public. And I think that politicians have played off of that quite effectively.

A lot of charter schools are non-union schools that take a lot of teachers from alternative tracks, like Teach For America. They do this in part because a lot of charter schools have very strong ideologies around how they want teachers to teach. And they find that starting with a younger or more inexperienced teacher allows them to more effectively inculcate those ideas.

Teaching is been seen as kind of a moral calling and not as an intellectual job.

I wrote a work of history, I looked at over 500 sources - I spent three-and-a-half years on the project. I think the most gratifying and wonderful thing about the reaction is that people are learning things from the history that feel relevant to today.

Just to deliver one high-quality 45 minute lesson requires many hours of planning in advance.