Superconductivity is among the most exciting of quantum phenomena in condensed matter physics, and has important applications across science and technology, from fusion reactors to particle accelerators. This self-contained text provides a comprehensive account of the physical foundations of superconductivity and related recent developments in the field. Beginning with a detailed description of the BSC theory of superconductivity, the book then describes the subsequent successes of this landmark theory and proceeds to more advanced topics such as Josephson effects and vortices. The strong coupling theory of superconductivity is introduced in later chapters, providing a springboard to important current research on hydride superconductors, which have displayed very high critical temperatures. Recent manifestations of superfluidity in ultracold atoms physics are also described. This book will give readers a solid grounding in the theory and applications of superconductivity, and an appreciation of its broader importance in the field of modern condensed matter physics.