This is my understanding of the situation: Traditionally, book publishers sell to stores at a wholesale price. Stores then mark up the price a bit and sell it

This is my understanding of the situation: Traditionally, book publishers sell to stores at a wholesale price. Stores then mark up the price a bit and sell it to the end consumers. Amazon then started selling books for prices below the wholesale price, deliberately taking a loss. The publishers got scared that this would destroy all non-Amazon channels, giving Amazon inordinate power over them. So they got together with Apple and set up a scheme where the publishers would all use the "agent" model. Instead of selling the books to Apple for a fixed wholesale price, they would set the prices however they liked, and Apple would take a cut of 30%. The publishers would then all refuse to sell to Amazon unless Amazon switched to the agent model. That, however, is pretty straight-forward collusion and against the law.