This book first describes fundamental knowledge on human thermal comfort, adaptive thermal comfort, thermal comfort in sleeping environments, modeling of human thermal comfort, and thermal comfort assessment using human trials. Next, it presents an in-depth review of concept progress and evaluation of various personal comfort system, summarizes important findings and feasible applications, current gaps as well as future research needs. The seven chapters included in this section are task/ambient conditioning systems, personalized ventilation systems, electric fans, personal comfort systems, thermoelectric systems, personal thermal management systems, and wearable personal thermal comfort systems. This book provides valuable guidance for personal comfort system design and further improvement on the personal comfort performance. It will be a valuable resource for academic researchers, engineers in industry, and government regulators in the field of sustainable buildings and built environment.