The papers in this volume were presented at TMRA 2006, the International Conference on Topic Maps Research and Applications, held October 11-12, 2006, in Leipzig, Germany. TMRA 2006 was the second conference of an annual series of international conferences dedicated to Topic Maps in research and industry. Topic maps are continuously gaining more and more attention in science and ind- try; they are "crossing the chasm." The TMRA series provides a platform for resear- ers in the topic maps community to meet for exciting exchanges in a stimulating setting. The uniqueness of TMRA is its focus on...