The document discusses building communities of practice around open textbooks to encourage their adoption, effective use, and sustainability. It describes a panel discussion with representatives from different academic disciplines who have formed communities of practice around open textbooks in their fields. The panelists discuss their experiences and lessons learned in starting these communities, using both synchronous and asynchronous communication methods, and getting instructors comfortable sharing materials. The goals are to share best practices, discuss challenges, and make plans to further develop these open textbook communities of practice.