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.

If you look at the early nineteenth century you see the idea that we educate children to be voters and to be participants in our popular democracy. And then at the turn of the century when more and more immigrants are coming into the schools, Americanization becomes a more explicit part of the agenda.

The first generation of school reformers I talk about - nineteenth century education reformer Horace Mann, Catharine Beecher - they are true believers in their vision for public education. They have a missionary zeal. And this to me connects them a lot to folks today, whether it's education activist Campbell Brown or former D.C. public schools chancellor Michelle Rhee. It's a righteous sense, a reform push that's driven by a strong belief in a particular set of solutions.

If you're afraid to talk to the other adults in your school it is definitely throughout history the hallmark of a failing school. When I was writing about the teachers' strike in New York City in 1968, the middle school where events triggered that strike was a place where teachers were known to hide in their classrooms.

Definitely we see throughout history that American teachers are asked to be very self-abnegating. They're not supposed to be concerned with the conditions of their labor, they're not supposed to care about pay. This is the kind of vision of the ideal teacher, which is again and again brought to the fore by reformers, the ideal teacher as someone who is passionately driven to serve children. Almost to the exclusion of a more pragmatic view of what the job actually entails.

Coming to the civil rights movement in the twentieth century, we begin to have this idea that's still with us today, which is that the main purpose of public education is closing achievement gaps.