An aspiration of modern cell biology is to 1) understand how the various cellular components assemble into a cell and 2) understand how cell function arises from the interaction of those components. How do cells form with a specific shape and size? How do they divide and how do cells decide where to divide? How does transport occur in the crowded cellular environment inside a cell? Mathematics has a role in helping answer such questions. Understanding of these phenomena also presents the opportunity to discover new deep mathematical concepts, particularly because it involves chemistry and physics acting across length-scales, from molecules to cells and tissues. BIRS has played a foundational role in the development of what has become known as Mathematical Biology of the Cell, by hosting regular workshops that have helped reveal principles behind how cellular components assemble and organize themselves to form discrete structures, distinct cellular compartments, and form patterns. The underlying goal of this meeting of interdisciplinary and diverse scientists is to understand the fundamental principles connecting cell signaling, geometry, transport, and mechanics.