Cellular membranes in eukaryotes are dynamic structures. The budding and fusion of vesicles, as well as the proper delivery of their contents, requires coordinated interactions between coat complexes, adaptor proteins, cargo molecules and cellular machinery including the cytoskeleton. The January 2012 issue of Nature Cell Biologypresents a series of review articles by leading scientists on recent developments in membrane dynamics — including endocytosis, and vesicle biogenesis and transport — and the importance of these processes in development and disease.