This volume provides a well-founded overview of the current state of research on a connected approach to mathematics learning in preschool and primary school. In 18 contributions, renowned scholars from early education and mathematics didactics present current research projects and findings in an accessible and practice-oriented manner, addressing key questions: What characterizes viable concepts of early mathematical education and how are they connected to mathematics instruction in primary school? How can appropriate learning support for early mathematics learning be designed? What professional competencies related to mathematics and mathematics didactics do educators and primary school teachers need? The book is aimed at educational professionals in preschool and primary school who are involved in leadership, specialist consulting, collaboration, and concept development.