This book is the translated version of Advanced Nanodielectrics: Fundamentals and Applications, which was published by the Investigating R&D Committee on Advanced Polymer Nanocomposite Dielectrics of the Institute of Electrical Engineers of Japan (IEEJ). The Japanese version is a winner of the IEEJ Outstanding Technical Report Award (2016). Nanocomposites are generally composed of host and guest materials. This book deals with the combination of a polymer as a host with an inorganic filler as a guest. It provides a detailed coverage on the processing and electrical properties of nanocomposites. It gives special consideration to the surface modification of particles, theoretical aspects of the interface, and computer simulation to help the reader develop an understanding of the characteristics of nanocomposites. Moreover, it discusses potential applications of nanocomposites in electric power and electronics sectors. The book is a definitive and practical handbook for beginners as well as experts.