Topic maps the new ISO standard ISO-IEC 13250 provide a bridge between the domains of knowledge representation and information management. Topics and topic associations build a structured semantic link network above information resources. Our research aims at visualizing this semantic layer efficiently, which is a critical issue as topic maps may contain millions of topics and associations. This paper is divided into 3 parts. First, we depict briefly basic topic maps concepts. Then, we review a few graph visualization techniques. Finally, we describe the visualization tool we developed at the Laboratoire d’Informatique de Paris 6 and study how this tool may be used and enhanced for topic maps visualization. Introduction: basic topic maps concepts According to , topic maps the new ISO standard ISO-IEC 13250 will become the answer for organizing and navigating through large and continuously growing information pools. They provide a "bridge" between the domains of knowledge representation and information management. This standard defines both an abstract data model and a serialization syntax to represent knowledge structures and to link them to information resources. Figure 1 describes topic maps basic concepts: topics, occurrences of topics and relationships (associations) between topics. For example, consider an information pool consisting of conference material. These resources have different roles (occurrence roles) articles, videos, charts, call for participation, etc. Examples of topics are XML Europe, Paris, France. Topics also have different types conference, city, country, etc. and associations exist between them: XLM Europe takes places in Paris, Paris is in France. In this example, there are two types of associations "takes place in" and "is in".