Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic fields are expelled from the material. The materials that exhibit these properties are called superconductors. In ordinary metallic conductors, resistance decreases gradually as its temperature is lowered down to near absolute zero. In a superconductor, the resistance drops to absolute zero below its characteristic critical temperature. Electric current that passes through a loop of superconducting wire can remain without any power source indefinitely. Superconductors are characterized by the Meissner effect, where the magnetic field lines are ejected completely from the interior of the superconductor during its transitions into the superconducting state. This book is a compilation of chapters that discuss the most vital concepts and emerging trends in the field of superconductors. The various studies that are constantly contributing towards advancing technologies and evolution of this field are examined in detail. This book includes contributions of experts and scientists which will provide innovative insights into this field.