ALT Extracellular vesicles (EVs) have emerged as important means of cell–cell communication, having the potential to transfer various cargoes – encompassing proteins, nucleic acids, metabolites or even entire organelles — between cells. By now, the importance of EV-mediated cell–cell communication has been documented in a plethora of physiological and pathological situations, across the different kingdoms. In addition, their secretion and cargo composition can change depending on the biological context, making EVs suitable biomarkers for several diseases. EVs have also been harnessed as drug delivery agents and standalone therapeutics. In this Collection, we have put together selected articles from across the Nature Portfolio that document the recent progress in understanding the biology of EV-mediated cell–cell communication and advances in clinical translation of EVs. The Collection has been divided into four parts: 1) Basic mechanisms, which overview the biogenesis and regulation of EV.