The III International Symposium of Terminology, organized by the research group IULATERM, was held at Universitat Pompeu Fabra in Barcelona from July 10 to 13, 2001. After the two first editions, devoted to Terminology and cultural models (1997) and to Terminology and cognition (1999), the three lectures of the l III Symposium are devoted to the analysis of sources of specialized knowledge and terminology. The first lecture, presented by Lita Lundquist (Copenhaguen Business School), is about the production of specialized knowledge. The second lecture, presented by Cristina Junyent (Observatori de la Comunicació Científica de la Universitat Pompeu Fabra), is about the problems of the transference of specialized knowledge. The third lecture, presented by Mercè Izquierdo (Departament de Didàctica de les Matemàtiques i de les Ciències Experimentals de la Universitat Autònoma de Barcelona), analyzes the teaching of specialized knowledge. The volumen has a four tex from the a lecture of Professor Josep Bernabeu-Mestre (University of Alacant) in the III Escuela Internacional de Verano de Terminología, and is about the terminology problems in historical research.