Organizational knowledge is much talked about but little understood. In this paper we set out to conceptualize organizational knowledge and explore its implications for knowledge management. We take on board Polanyi’s insight concerning the personal character of knowledge and fuse it with Wittgenstein’s insight that all knowledge is, in a fundamental way, collective. We do this in order to show, on the one hand, how individuals appropriate knowledge and expand their knowledge repertoires, and, on the other hand, how knowledge, in organized contexts, becomes organizational. Our claim is that knowledge is the individual capability to draw distinctions, within a domain of action, based on an appreciation of context or theory, or both. Organizational knowledge is the capability members of an organization have developed to draw distinctions in the process of carrying out their work, in particular concrete contexts, by enacting sets of generalizations whose application depends on historically evolved collective understandings. Following our theoretical exploration of organizational knowledge, we report the findings of a case study carried out at a call centre in Panafon, in Greece. Finally, we explore the implications of our argument by focusing on the links between knowledge and action on the one hand, and the management of organizational knowledge on the other. We argue that practical mastery needs to be supplemented by a quasi-theoretical understanding of what individuals are doing when they exercise that mastery, and this is what knowledge management should be aiming at. Knowledge management, we suggest, is the dynamic process of turning an unreflective practice into a reflective one by elucidating the rules guiding the activities of the practice, by helping give a particular shape to collective understandings, and by facilitating the emergence of heuristic knowledge.