In this text, Shigeji Fujita and Salvador Godoy guide first and second-year graduate students through the essential aspects of superconductivity. The authors open with five preparatory chapters thoroughly reviewing a number of advanced physical concepts-such as free-electron model of a metal, theory of lattice vibrations, and Bloch electrons. The remaining chapters deal with the theory of superconductivity-describing the basic properties of type I, type II compound, and high-T_c superconductors as well as treating quasi-particles using Heisenberg's equation of motion. The book includes step-by-step derivations of mathematical formulas, sample problems, and illustrations.