The idea of knowledge as the source of competitive advantage has been celebrated in the management literature for some time. However, our understanding of how knowledge emerges and develops in the actual work practices is still relatively limited. The argument of this paper is that an approach called 'communities of practice' offers a relatively coherent view of the social processes of knowledge creation. The paper introduces the 'communities of practice' approach as a general scientific perspective for making sense of and planning organizational knowledge management programs in a more effective and contextually sensitive way. However, at the same time it is noted that the move to a socio-cultural inquiry of knowledge creation processes is associated with a broader shift in thinking about organizations and organizing and that a full awareness of the practical complexities and contradictions inherent in the ideas around 'communities' and 'practices' needs to accompany the application of this new vocabulary of managing and learning.