Topic Maps standard (ISO-13250) has been gradually recognized as an emerging standard for information exploration and knowledge organization. One advantage of topic maps is that they enable a user to navigate and access the documents he wants in an organized manner, rather than browsing through hyperlinks that are generally unstructured and often misleading. Nowadays, the topic maps are generally manually constructed by domain experts or users since the functionality and feasibility of automatically generated topic maps still in progress. In this paper, we give an overview of Topic Map building approaches. These approaches take as input different data types: structured documents, structured knowledge, unstructured documents and semi-structured data, and propose different techniques to build a Topic Map such as merging, mapping from RDF to TM and learning techniques. Some other research works are dedicated to cooperative Topic Map building and another research area deals with automatic generation of TM from XML documents.