The Topic Map paradigm can be viewed as a new ‘data base’ approach for knowledge bases and the representation of knowledge structures. Relational databases use the query language SQL as a standardized interface between applications that implement the business logic and the database containing the relational data. The Topic Map community has expressed a need for a comparable query language for topic maps. So in May 2001 ISO JTC1 SC34 officially started a new standards initiative, TMQL (Topic Map Query Language). Why TMQL? What are the initiative's stated requirements? What is the current standarization status? What are the use cases and application scenarios?