The first volume of the 31st annual proceedings of the International Group for the Psychology of Mathematics Education conference presents plenary lectures; research forums; discussion groups; working sessions; short oral communications; and posters from the meeting. Plenary lecture papers include: (1) On Humanistic Mathematics Education: A Personal Coming of Age? (Chris Breen); (2) Certainty, Explanation and Creativity in Mathematics (Michael Otte); (3) I Need the Teacher to Tell Me If I Am Right or Wrong (Anna Sierpinska); and (4) School Mathematics and Cultivation of Mind (Jeong-Ho Woo). Plenary panel papers include: (1) Introduction to the PME Plenary Panel, "School Mathematics for Humanity Education" (Koeno Gravemeijer); (2) Humanizing the Theoretical and the Practical for Mathematics Education (Cristina Frade); (3) Making Mathematics More Mundane--A Semiotic Approach (Willibald Dorfler); (4) Mathematics: A Human Potential (Martin A. Simon); and (4) Need for Humanising Mathematics Education (Masataka Koyama). The first research forum, Learning through Teaching: Development of Teachers' Knowledge in Practice (RF01) includes: (1) A View on the Teachers' Opportunities to Learn Mathematics through Teaching (Roza Leikin and Rina Zazkis); (2) Integrating Virtual and Face-to-Face Practice: A Model for Continuing Teacher Education (Marcelo C. Borba); (3) Teachers' Learning Reified: The Professional Growth of Inservice Teachers through Numeracy Task Design (Peter Liljedahl); (4) Constraints on What Teachers Can Learn from their Practice: Teachers' Assimilatory Schemes (Martin A. Simon); and (5) What and How Might Teachers Learn via Teaching: Contributions to Closing an Unspoken Gap (Ron Tzur). The second research forum, Researching Change in Early Career Teachers (RF02), includes: (1) Introduction (Peter Sullivan); (2) Researching Relief of Mathematics Anxiety among Pre-Service Elementary School Teachers (Markku S. Hannula, Peter Liljedahl, Raimo Kaasila, and Bettina Rosken);(3) Teachers' Learning from Learning Studies: An Example of Teaching and Learning Fractions in Primary Four (Lo Mun Ling and Ulla Runesson); (4) Tracking Teachers' Learning in Professional Development Centered on Classroom Artifacts (Lynn T. Goldsmith and Nanette Seago); (5) Teacher Change in the Context of Addressing Students' Special Needs in Mathematics (Orit Zaslavsky and Liora Linchevski); (6) Researching Change in Prospective and Beginning Teachers (Laurinda Brown and Alf Coles); and (7) Summary and Conclusions (Markku S. Hannula). Information relating to discussion groups, working sessions, short oral communications, and poster presentations conclude this volume of the 31st proceedings. (Individual papers contain references.)