The Josephson Junction is a type of electronic circuit capable of switching at very high speeds when operated at temperatures approaching absolute zero. It exploits the phenomenon of superconductivity, the ability of certain materials to conduct electric current with practically zero resistance. This book presents new and important research in superconductivity. This includes optical properties, magneto-optics and surface acoustic waves, microwave responses, theories of superconductivity, synthesis in electronic applications and high temperature superconductivity.