This chapter looks at graphic strategies to reference knowledge and to make it more accessible through interactive knowledge maps. It discusses pragmatic ways of classifying knowledge maps to give an overview of their application contexts and formats. In the chapter, we show where and how the term knowledge map has been previously used and which criteria must be met in a sound and useful knowledge map classification that can support knowledge management processes and strategies. Various classification principles are presented and discussed. A table then matches map formats to knowledge management purposes and knowledge-related contents in order to serve as a selection and organizing framework. Examples of some of the main types of knowledge maps are presented to illustrate the varieties of knowledge mapping present in the classification. The article concludes by discussing its limitations and future research questions in the area of knowledge mapping.