The set of certain physical properties which are seen in specific materials is known as superconductivity. Due to these physical properties, the electrical resistance vanishes and the magnetic flux fields are expelled. The materials which show these properties are known as superconductors. The resistance in normal metallic conductors decreases gradually when the temperature is lowered even close to absolute zero. In superconductors, there is a distinctive critical temperature, below which the resistance suddenly drops to zero. Therefore, a loop of superconducting wire can keep on conducting electric current indefinitely, without any power source. This book traces the progress of this field and highlights some of its key concepts. Most of the topics introduced in it cover new techniques and the applications of superconductivity. The book is appropriate for students seeking detailed information in this area as well as for experts.