As the smallest autonomous biological system, the cell defines a fundamental scale of organization in biology. The complex assemblies of cells during development lead to the emergence of much larger scales of organization underlying novel functions associated with the life and reproduction of multicellular organisms. These different scales of organization raise fundamental questions in the field of cell and developmental biology: How are subcellular cell structures and dynamics controlled? How can biochemical and mechanical cell interactions drive the emergence of complex organs? How can tissue or organ-scale processes in turn modulate cell organization and dynamics for the lifelong biology of multicellular systems? How these processes have been selected throughout evolution and how their dysfunction leads to various pathologies?