Preface. Cognitive, Developmental and Motivational Aspects. Conceptual change research: state-of-the-art and future directions (S. Vosniadou). The development of ontological categories: stable dimensions and changing concepts (S. Pauen). Motivational beliefs as resources for and constraints on conceptual change (P.R. Pintrich). Situational Aspects. Conceptual change and contextualization (O. Hallden). Systems of signs and conceptual change (T. Nunes). Concepts, cognition and discourse. From mental structures to discursive tools (R. Saljo). Knowledge, belief, and opinion: a sociologist's view of conceptual change (D. Kalekin-Fishman). Domain-Specific Aspects. Knowledge restructuring in an economic subdomain: banking (A.E. Berti). Conflicting data and conceptual change in history experts (M. Limon, M. Carretero). When change does not mean replacement: different representations for different contexts (J.I. Pozo et al.). Children's conceptions about the role of realworld knowledge in mathematical modelling: analysis and improvement (L. Verschaffel et al.). Instructional Aspects. Task-dependent construction of mental models as a basis for conceptual change (W. Schnotz, A. Preus). Constraints on the effectiveness of diagrams as resources for conceptual change (R. Lowe). Computer-assisted instructional strategies for promoting conceptual change (J.A. Biemans). Conceptual change approaches in science education (R. Duit).