As free online courses draw students to star professors at prestigious colleges, Peer 2 Peer University asks whether instructors are needed at all. This article features Peer 2 Peer University, a three-year-old online institution where students learn together, at no charge, using materials found on the Web. The unusual institution, where anyone with a passion for a topic can set up a course, is experimenting with ways that students can navigate together through open courseware that's free on the Web. In the process, the project is stimulating discussion in open-education circles about the evolving roles of peers and professors in the growing number of free online courses. Much of P2PU's traffic comes from word of mouth; the providers attracting most of the attention in the open-course world are the big-name universities offering massive open online courses, or MOOC's.