Today, more than 20 million students are enrolled in American colleges, but “the foundations of the modern higher education system really started a long time ago — more than 100 years ago,” says David Deming, professor of public policy at the Harvard Kennedy School and the Harvard Graduate School of Education. “The real formative period for U.S. higher education was more or less 1890 to 1940, when college started to be something that wasn’t just a vocation for people going to school to get a religious education or for the few and the wealthy.