2020’s special issue puts the spotlight on the pancreas and its role in health and in diabetes. With discussions on the anatomy of the whole pancreas to the role of the individual cellular components and their intra- and intercellular interactions, this series of reviews aims to provide an in-depth overview of what we know about this important organ and what we are yet to discover. Topics include: insulin production and diabetes-associated abnormalities; beta cells as autoimmune targets; functional changes in the ageing beta cell; pancreas/islet/beta cell transplant strategies; alpha cell–beta cell communication; the islet microenvironment and endocrine cell function; central nervous system control of the endocrine pancreas; and approaches to connect molecular profiles with functional properties underlying insulin secretion.