This conference proceedings from annual conference of the North American Chapter of the International Group for the Psychology of Mathematics Education (PME-NA) contains the following research papers: "The Interactive Nature of Cognition and Affect in the Learning of Mathematics: Two Case Studies" (T.J. Bassarear); "The Value of Concept Forming in Mathematics in Schools with Second Language Medium of Instruction" (F.H. Swart); "Conceptual Difficulties in Algebra Word Problems Having Only One Variable" (A. Ganguli); "The Process of Mathematization in Problem Solving Within a Computer Environment: A Functional Approach" (C. Kieran, A. Boileau, & M. Garansson); "Abstract Impressionist Algebra" (D. Kirshner); "Canceling Cancellation: The Role of Worked-out Examples in Unlearning a Procedural Error" (M.S. Smith & E. Silver); "Methodological Elements for the Reconstruction of an Analysis Didactics: The Case Study of Convergence" (R.M. Farfan); "Concept Image in Its Origins with Particular Reference to Taylor's Series" (R.C. Uriza); "About the Heritage in Calculus Textbooks: A Definition of Integral or the Fundamental Theorem of Calculus" (F.C. Osorio); "Software Design for Learning Mathematics" (I. Harel); "Proportional Reasoning Strategies: Results of a Teaching Experiment Using Concrete Representations" (M. Maxwell, C. Luke, J. Poholsky, L. Pattison-Gordon, S. Turner, & J. Kaput); "The Computer as an Aid to Formalizing Arithmetic Generalizations" (D.M. Peck); "The Kindergartners' Procedural Understanding of Number: An International Study" (J.C. Bergeron & N. Herscovics); "Effects of Instruction On Number Magnitude" (J. Sowder & Z. Markovits); "First Graders' Understanding of the Pre-Concepts of Number" (A. Bergeron); "The Role of Spatial Patterns in Number Development" (G.H. Wheatley & J.J. Lo); "Symbolic Representation of Addition and Subtraction Word Problems: Number Sentence Errors" (H.C. Bebout & J. Ishida); "Case Studies of Children's Understanding of the Concept of Length and Its Measure" (B. Heraud); "Relationship between Spatial Ability and Mathematics Knowledge" (D. Brown & G. Wheatley); "Reflection, Point Symmetry, and LOGO" (E. Gallou-Dumiel); "Story Editing and Diagnosis of Geometry Understanding" (G.W. Bright); "The van Hiele Model of Geometric Understanding and Geometric Misconceptions in Gifted Sixth Through Eighth Graders" (M.M. Mason); "The Understanding of Transformation Geometry Concepts of Secondary School Students in Singapore" (Y.P. Soon & J. Flake); "Proportional Reasoning in Young Adolescents: An Analysis of Strategies" (S. Larson, M. Behr, G. Harel, T. Post, & R. Lesh); "Young Children's Theorems-in-action on Multiplicative Word Problems" (V.L. Kouba); "Student Use of Rational Number Reasoning in Area Comparison Tasks" (B.E. Armstrong); "Multiplicative Word Problems - Recent Developments" (A. Bell); "Children's Perceptions of Multiplications Across Pictorial Models" (C.B. Beattys); "Preservice Elementary Teachers' Understanding of Proportional Reasoning Missing Value Problems" (N. Bezuk); "Using Research in Rational Number Learning to Study Intermediate Teachers' Pedagogical Knowledge" (R.E. Orton, T. Post, M. Behr, & R. Lesh); "The Historical Development of Logarithms and Implications for the Study of Multiplicative Structures" (E. Smith & J. Confrey); "Children's Representations of Arithmetic Properties in Small Group Problem-Solving Activities" (A. Alston); "Children's Metacognitive Knowledge about Mathematics and Mathematical Problem Solving" (F.R. Curcio & T. DeFranco); "Building a Qualitative Perspective Before Formalizing Procedures: Graphical Representations as a Foundation for Trigonometric Identities" (S. Dugdale); "Area and Perimeter, Applied Problem Solving and Constructivism" (J. Pace); "Problem Posing by Middle School Mathematics Teachers" (E.A. Silver & J. Mamona); "Factor Structure of Junior High School Students' Responses to Metacognition Statements for a Non-Routine Problem" (D. Hecht & C. Tittle); "Beliefs about Causes of Success and Failure in Mathematical Problem Solving: Two Teachers' Perspectives" (D. Najee-ullah, L. Hart, & K. Schultz); "Prospective Elementary Teachers' Beliefs about Mathematics" (E.H. Jakubowski & M. Chappell); "Prospective Elementary Teachers' Conceptions about the Teaching and Learning of Mathematics in the Context of Working with Ratios" (M. Civil); "Changing Preservice Teacher's Beliefs about Mathematics Education" (P. Schram, S. Wilcox, G. Lappan, & P. Lanier); "Learning to Teach Mathematics: A Report on the Methodology of an Eclectic Investigation" (D. Jones, C. Brown, R. Underhill, P. Agard, H. Borko, & M. Eisenhart); "Elementary Teachers and Problem Solving: Teacher Reactions and Student Results" (J.K. Stonewater); "The Use of 'Mini-Interviews' by 'Orthopedagogues': Three Case Studies" (J.J. Dionne, M. Fitzback-Labrecque); "Developing Probability and Statistics from Problem Situations: An Experimental Course for Prospective Teachers" (G.T. Klein); "Changes in Pre- and In-service Teachers' Views of Priorities in Elementary Mathematics as a Function of Training" (R. Kaplan); "Constructivism: A Model for Relearning Mathematics" (L.C. Koch); "Examining Change in Teachers' Thinking Through Collaborative Research" (B.A. Onslow); "The Mathematics Teacher as Researcher in the Diagnosis of Conceptual Understanding" (J. Schmittau). Includes a listing of author addresses. (MKR)