This book presents the recent progress in the field of nanophotonics. It contains review-like chapters focusing on various but mutually related topics in nanophotonics written by the world's leading scientists. Following the elaboration of the idea of nanophotonics, much theoretical and experimental work has been carried out, and several novel photonic devices, high-resolution fabrication, highly efficient energy conversion, and novel information processing have been developed in these years. Novel theoretical models describing the nanometric light-matter interaction, nonequilibrium statistical mechanical models for photon breeding processes and near-field-assisted chemical reactions as well as light-matter interaction are also explained in this book. It describes dressed photon technology and its applications, including implementation of nanophotonic devices and systems, fabrication methods and performance characteristics of ultrathin, ultraflexible organic light-emitting diodes, organic solar cells and organic transistors.