Geoff Pullum observes, in passing, that “the notion of small textbooks has just vanished in modern America (800 pages is commonplace, 400 is positively wimpy, and under 200 is close to unknown).” Why? I figure it’s for the same reason textbooks are so expensive: there’s a third-party buyer problem. Professors do the choosing, while students do the buying. Thus, professors have little incentive to choose inexpensive textbooks.
But why the displacement of small, narrow-focus texts by massive, encyclopedic ones? A textbook that covers all the topics a professor intends to cover provides one-stop shopping, so the professor doesn’t have to order multiple texts. But not all professors of a given subject want to cover the same topics. For instance, I teach intermediate microeconomics. I like to cover the theory of risk and uncertainty, theories of (alleged) market failure, and game theory. But another professor might consider those topics less important, and spend more time on (say) labor markets, a topic I skimp on. A smaller textbook covering fewer topics would likely appeal to just one of us, while a comprehensive text will get business from both. As a side effect, all students end up buying a microeconomics text with numerous chapters that go unused.
Here’s the economic puzzle: Why has this phenomenon only appeared in recent decades? Professors have always chosen the texts that students have to buy. So why haven’t textbooks always been huge and expensive? What’s changed?