Tim Wu, in Times op-ed:

Teaching is a profession with its own ethical duties; students are both our charges and a captive market. I don’t think there’s anything wrong with assigning an expensive book if it is really worth the money and the alternatives are inadequate. (It helps if there’s a good used or rental market). But we at least owe our students the time to make sure we aren’t just absent-mindedly ripping them off.

Wu’s right, but the piece is weirdly silent on the publishers themselves. The “root problem” isn’t professors spending their students’ money: It’s a textbook-publishing oligopoly. Professors, at most, are half-witting accomplices.