Making knowledge visible so that it can be better accessed, discussed, valued, or generally managed is a longstanding objective in knowledge management (see Sparrow, 1998). Knowledge maps, knowledge cartographies, or knowledge landscapes are often heard terms that are nevertheless rarely defined, described, or demonstrated. In this article, we review the state of the art in the area of knowledge visualization, and describe its background and perspectives. We define the concept and differentiate it from other approaches, such as information visualization or visual communication. Core knowledge visualization types, such as conceptual diagrams or visual metaphors, are distinguished, and examples of their application in business are shown and discussed. Implications for research and practice are summarized, and future trends in this domain are outlined.