This book focuses on the numerous energy harvesting techniques and their system implementation towards the fulfilment of energy requirements in compact electronic devices. These cover a wide range of applications in portable devices, bio-medical services, agriculture needs, mechanical systems, sensor networks, automobiles, food sector, home appliances, industry needs, etc. The authors detail energy harvesting methods using the latest technologies in acoustics, bio-chemical, thermal, artificial light, fluid flow, vibrations, EM energy, RF energy, piezoelectric, electrostatic, photovoltaic, thermoelectric, hybrid harvesting, ultrasonic, infrared, light, wind, and solar. The book is intended for researchers, academics, professionals, and students in energy harvesting.