Superconductivity is a striking phenomenon that has attracted the attention of physicists, chemists, material scientists, engineers, and also the non-technical public. The discovery of high-Tc cuprates opened up a new class of materials in this field. This significant and exciting discovery has posed two new problems: of making High-Tc materials available to technology at room temperature on one hand and of exploring the possible mechanism of High-Tc superconductivity on the other. The beginning of the 21st century sees superconductor applications reaching important milestones. Superconductors now make possible the most advanced experiments in chemistry, biochemistry, particle physics and health sciences. Superconductors are also becoming part of the fabric of modern-day life. This outstanding and invaluable volume has been very systematically structured and organised covering all aspects of superconductivity. The first five chapters deal with basic principles and microscopic weak coupling BCS theory of superconductivity. Chapters 6 to 8 are devoted to high-Tc cuprates covering experimental results and theories. Chapter 9 is diverted to new emerging superconductors and the last chapter describes the potential applications of superconductors.