Well known for its accessibility to graduate students and experimental physicists, this volume emphasizes physical arguments and minimizes theoretical formalism. This second edition features improvements by the author that enhance its user-friendliness and value as a reference. Starting with a historical overview, the text proceeds with an introduction to the electrodynamics of superconductors and presents expositions of the Bardeen-Cooper-Schrieffer and Ginzburg-Landau theories. Additional subjects include magnetic properties of classic type II superconductors; the Josephson effect; fluctuation effects in classic superconductors; the high-temperature superconductors; and nonequilibrium superconductivity.