This proceedings of the annual conference of the International Group for the Psychology of Mathematics Education (PME) includes the following papers: "Transformations Accelerees de l'Education Scientifique Pendant la Revolution Francaise" (Jean Dhombres); "Building on the Knowledge of Students and Teachers" (Thomas P. Carpenter & Elizabeth Fennema); "Hardiesse et Raison des Recherches Francaises en Didactique des Mathematiques" (Colette Laborde); and "Mathematical Literacy for All Experiences and Problems" (Paolo Boero); "Re-Exploring Familiar Concepts with a New Representation" (A. Arcavi & R. Nachmias); "La Construction du Concept de Figure chez les Eleves de 12 Ans" (G. Arsac); "The Role of Conceptual Models in the Activity of Problem Solving" (F. Arzarello); "How to See Equality in the Difference: An Old Problem with Educational Value" (L. Bazzini); "Exploring Children's Perceptions of Multiplication Through Pictorial Representations" (C. Beattys & C. Maher); "Affective Aspects of the Learning of Mathematics" (M. Beharie & Y. Naidoo); "A Conflict and Investigation Teaching Method and an Individualized Learning Scheme: A Comparative Experiment on the Teaching of Fractions" (A. Bell & D. Bassford); "Some Results of a Large Scale Evaluation of the New Syllabus at French College Level" (A. Bodin); "Grade 8 Students' Understanding of Structural Properties in Mathematics" (L.R. Booth); "Unconditional Mathematics" (L. Brandau & K. Richmond); "Comparison of Teacher and Pupil Perceptions of the Learning Environment in Mathematics" (M. Carmeli, D. Ben-Chaim, & B. Fresko); "Numeracy Without Schooling" (T.N. Carraher); "Strategies and Error Patterns in Solving Rotation Transformation" (C. Chien); "A Solo Mapping Procedure" (K.F. Collis & J.M. Watson); "Le Discours Justificatif en Mathematique: L'implication du Locuteur selon la Representation du Referent" (D. Coquin-Viennot); "Qualitative and Quantitative Time Reasoning in Children" (J. Crepault & S. Samartzis); "The Multidimensional Nature of the Pre-Concepts of Number" (C. Dassa, J.C. Bergeron, & N. Herscovics); "Protocols of Actions as a Cognitive Tool for Knowledge Construction" (W. Dorfler); "Representations du Fonctionnement d'une Procedure Recursive en Logo" (C. Dupuis & D. Guin); "Langage et Representation dans l'Apprentissage d'une Demarche Deductive" (R. Duval); "Towards a Theory of Transition" (N.F. Ellerton & M.A. Clements); "Validation d'un Logiciel d'Aide a la Resolution de Problemes Additifs" (M.C. Escarabajal & M. Kastenbaum); "How Big is an Infinite Set? Exploration of Children's Ideas" (R. Falk & S. Ben-Lavy); "Hypothetical Reasoning in the Resolution of Applied Mathematical Problems at the Age of 8-10" (P.L. Ferrari); "Two Different Views of Fractions: Fractionating and Operating" (O. Figueras); "Psychological Difficulties in Understanding the Principle of Mathematical Induction" (E. Fischbein & I. Engel); "Incipient 'Algebraic' Thinking in Pre-Algebra Students" (A. Friedlander, R. Hershkowitz, & A. Arcavi); and "Development of the Process Conception of Function by Pre-Service Teachers in a Discrete Mathematics Course" (E. Dubinsky, J. Hawks, D.A. Nichols). Includes a listing of working group and discussion group topics and organizers. (MKR)