Over the past decade, a small revolution has taken place at some of the world's leading universities, as they have started to provide free access to undergraduate course materials--including syllabi, assignments, and lectures--to anyone with an Internet connection. Yale offers high-quality audio and video recordings of a careful selection of popular lectures, MIT supplies digital materials for nearly all of its courses, Carnegie Mellon boasts a purpose-built interactive learning environment, and some of the most selective universities in India have created a vast body of online content in...