This document discusses the history and definition of communities of practice (CoPs) as groups that share a common interest in a topic and deepen their knowledge through ongoing interaction. It provides examples of CoP activities like face-to-face meetings, online discussions, blogs, multicountry research, and publications. Lessons learned are that CoPs should build relationships by combining in-person and online activities, encourage participation from relevant institutions, and secure sustainable funding to empower core members and facilitate activities over the long term.