With the release of the iBooks and iBooks Author applications, I think the time has come for crowdsourcing the textbook industry. Generally speaking, the curriculums of K-12 and even many college degrees have stabilized, meaning that the value of their textbooks should be dropping.

In economic terms, the supply of most knowledge—globally, certainly—has been increasing, so the cost of that knowledge should be decreasing.

Why should the textbook companies continue to make $120 for an introductory physics textbook that hasn’t changed in 10 years?