Welcome to this compendium of articles that reviews sensor research in all its facets, ranging from the physical and chemical nature of sensing at the molecular level, to the monitoring of buildings and human behaviour. The theme of this issue, ‘Sensors in technology and nature’, was the theme of the ‘Sensors Day’ (http://cdt.sensors.cam.ac.uk/sensors-day-2015), a conference organized at the University of Cambridge on the 16 October 2015, to reflect the diversity of research going on in this field.