This book presents trading in local energy markets and communities. It covers electrical, business, economics, telecommunication, information technology (IT), environment, building, industrial, and computer science and examines the intersections of these areas with these markets and communities. Additionally, it delivers an vision for local trading and communities in smart cities. Since it also lays out concepts, structures, and technologies in a variety of applications intertwined with future smart cities, readers running businesses of all types will find material of use in the book. Manufacturing firms, electric generation, transmission and distribution utilities, hardware and software computer companies, automation and control manufacturing firms, and other industries will be able to use this book to enhance their energy operations, improve their comfort and privacy, as well as to increase the benefit from the energy system. This book is also used as a textbook for graduate level courses.