Knowing is an enacted, communicated process that is difficult to observe, let alone manage, in organizations. Communities of practice (CoPs) offer a productive solution for improving knowledge and knowledge management, but the communicative processes that enact CoPs have not been explored, leaving CoPs as an organizational black box. This research extends CoP theory as a means to determine the presence of a CoP and distinguish between various CoPs, and as a practical means to evaluate the communicative processes of organizational knowledge. CoPs enact the communicative nature of knowing through the elements of mutual engagement, negotiation of a joint enterprise, and shared repertoire. Specifically, two groups of volunteers are examined through a combination of participation, observation, and interviews in order to explore CoP theory as a dynamic system for examining and evaluating organizational knowledge. (Contains 1 table.)