Recognising or monitoring human activities has significant potential for building innovative systems across a wide range of domains, including healthcare, smart home, sports, industry, security, and human-computer interaction. This reprint features nine of the latest studies on sensor-based Human Activity Recognition (HAR), which aims at recognising activities by exploiting and integrating data obtained from various sensors, like wearable, object, and ambient sensors, as well as vision sensors. In particular, these studies address various key aspects of sensor-based HAR, spanning methodologies, sensor technologies, and dataset collection, as well as the development and evaluation of actual systems. The editor hopes that this reprint will encourage many researchers to explore this attractive and important research field.