[Jonathan Zimmerman teaches history and education at New York University and lives in Narberth. He is the author of "Small Wonder: The Little Red Schoolhouse in History and Memory" (Yale University Press).]

In his State of the Union Address this week, President Obama pledged to help American schools recruit and train 100,000 new science and math teachers over the next 10 years. But he left out the scientists and the mathematicians - as well as the economists, anthropologists, political scientists, and historians.

That's a big problem. Since the 1980s, scholars in the academic disciplines have largely ceded the matter of K-12 schooling to professors of education. If we're serious about improving our schools, we need to bring the disciplines back in.

As a professor with one foot in each camp - a disciplinary department and an education school - I'm acutely aware of the divide between them. People in the disciplines generally dismiss education, and education professors disdain the disciplines. It's mutual.

It's also destructive. Too many ed schools still believe the myth that you can teach students "methods" of education without rigorous attention to the disciplines they will be teaching. And most disciplinary scholars still think anyone who understands a subject can teach it.

They're both wrong. We've all had teachers who didn't know enough about a subject to teach it well. And we've had teachers who knew their material backward and forward, but couldn't communicate it to others.

So, besides helping schools hire new teachers in science, math, and engineering, as Obama promised to do Tuesday, he should also establish incentives for collaboration between education schools and the disciplines....