Following the successful first edition, this new book aims to comprehensively summarize the latest research progress in the mechanical-to-electrical energy conversion properties and applications of electrospun nanofibers. It covers the basic fabrication methods of electrospun nanofibers, the piezoelectric and triboelectric devices based on electrospun nanofibers, the energy harvesting properties of novel nanofiber materials, and the application performance of the nanofibers in acoustoelectric conversion, sound detection, speech recognition, electronic skin, tissue engineering, and health monitoring.