Collaboration and sharing are critical to modern innovation environments, yet the conventional model of intellectual property is premised on the sole inventor. This chapter surveys the various institutional arrangements that challenge that premise—ex ante licensing, open innovation, user innovation, peer production, and knowledge commons. It argues that in innovation environments marked by collaboration, the common economic challenge is not sustaining incentives to innovate, as in the classic model, but overcoming barriers to information exchange. Intellectual property can, in some circumstances, facilitate the diffusion of information. But the role that IP plays in collaborative environments is complex and context-specific, as the existing empirical studies of open innovation and its variants have revealed. This suggests that intellectual property policy ought to be pluralistic, allowing for the development of a variety of institutional solutions to the challenges of collaboration.