Superconductivity refers to a set of specific physical properties exhibited by certain materials. These properties result in the complete elimination of electrical resistance and the expulsion of magnetic flux fields. Materials that demonstrate these characteristics are termed superconductors. Unlike normal metallic conductors, where resistance diminishes gradually with decreasing temperature, superconductors exhibit a distinct critical temperature. Below this temperature, the resistance abruptly drops to zero. Consequently, a loop of superconducting wire can sustain electric current indefinitely without requiring a power source. Superconductivity is an upcoming field of science that has undergone rapid development over the past few decades. Most of the topics introduced in this book cover new techniques and the applications of superconductivity. Those with an interest in this field would find this book helpful.