The papers in this volume were presented at TMRA 2007, the International Conference on Topic Maps Research and Applications, held October 11–12, 2007, in Leipzig, Germany. TMRA 2007 was the third conference in an annual series of international conferences dedicated to Topic Maps in science and industry. The motto of TMRA 2007 was “Scaling Topic Maps.” Taken literally the motto implies developing Topic Maps approaches that scale to large data and user volumes. This is a very real and useful research problem which is addressed by many of the contributions to the conference. But there is an even broader interpretation of the motto: wide adoption of Topic Maps in academia and industry. This is an equally important problem, and one that the TMRA conference series exists to help solve. And there is a more fanciful view on the motto. To “scale” can also mean to climb, so for the attendees the conference provided a way to “scale the mountain of Topic Maps.” In all these ways TMRA 2007 helped to scale Topic Maps.