Knowledge Management and Knowledge Management Systems are slowly but surely capturing the attention of many organisations in a quest for competitive advantage. Like many other computing fads before them, there is no shortage of recipes by its proponents. This chapter discusses the emerging discipline of Knowledge Management in computing and explains the concepts underlying Knowledge Management Systems that will lead to a better development and implementation of these systems. In particular, it tackles the conceptual confusion about data, information, and knowledge, which appears to be finding its way into the Knowledge Management literature. The terms, ‘capta’ (Checkland, Howell, 1998) and ‘constructed data’ (Flood, 1999), are used in analysing these concepts to clear some of the confusion surrounding them. The use of these terms also highlights our (the IT community) taking for granted assumptions about the hierarchical relationship and the more insightful emergent relationships.