Daftar Isi:1. How Much as Compared to What Relative Magnitude as a Key Idea in Mathematics Cognition 2. From Intuitive Spatial Measurement to Understanding of Units 3. Spatial Reasoning A Critical Problem-Solving Tool in Children s Mathematics Strategy Tool-Kit 4. More Space Better Mathematics Is Space a Powerful Tool or a Cornerstone for Understanding Arithmetic 5. What Processes Underlie the Relation Between Spatial Skill and Mathematics 6. Part I Commentary 1 Deepening the Analysis of Students Reasoning About Length 7. Part I Commentary 2 Visualization in School Mathematics Analyzed from Two Points of View 8. Part I Commentary 3 Proposing a Pedagogical Framework for the Teaching and Learning of Spatial Skills A Commentary on Three Chapters 9. Part I Commentary 4 Turning to Temporality in Research on Spatial Reasoning 10. Analyzing the Relation Between Spatial and Geometric Reasoning for Elementary and Middle School Students 11. Learning Through and from Drawing in Early Years Geometry 12. The Interaction Between Spatial Reasoning Constructs and Mathematics Understandings in Elementary Classrooms 13. Geometric Modeling of Mesospace Objects A Task its Didactical Variables and the Mathematics at Stake 14. Visualization Abilities and Complexity of Reasoning in Mathematically Gifted Students Collaborative Solutions to a Visualization Task A Networked Analysis 15. Part II Commentary 1 Mathematics Educators Perspectives on Spatial Visualization and Mathematical Reasoning 16. Part II Commentary 2 Disparities and Opportunities Plotting a New Course for Research on Spatial Visualization and Mathematics 17. Part II Commentary 3 Linking Spatial and Mathematical Thinking The Search for Mechanism 18. On the Multitude of Mathematics Skills Spatial-Numerical Associations and Geometry Skill