There’s a mildly interesting exchange on the NY Times website about textbook prices. The authors and commenters hit most of the pertinent facts, with a fair sprinkling of misinformation as well (like implying that the typical textbook author is getting rich off the enterprise), but one issue that seems to be missed in the role that used book sales play in the pricing spiral.
Used books aren’t just a bargain for the students and a way to increase profits for the bookstore–they also induce higher prices of new text books. When a new book is sold, everyone gets a cut. When a used book is sold, the publisher and the authors get nothing. With the used book market becoming more and more efficient, proportionally fewer students are buying new books, which means fewer sales are producing revenue for the publishers and authors. That in turn cause the publishers to demand shorter times between editions and higher prices on new books. Which in turn produces more demand for used books. The spiral is unsustainable and will eventually force authors of lower-selling alternatives out of the market completely.