Superstrings and M-theory: provocative and controversial, but unarguably one of the most interesting and active areas of research in current physics. Called by some, "the theory of everything," superstrings may solve a problem that has eluded physicists for the past 50 years, the final unification of the two great theories of the twentieth century, general relativity and quantum field theory.Now, here is a thoroughly revised, second edition of a course-tested comprehensive introductory graduate text on superstrings which stresses the most current areas of interest, not covered in other presentations, including:· Four-dimensional superstrings· Kac-Moody algebras · Teichmüller spaces and Calabi-Yau manifolds · M-theory Membranes and D-branes · Duality and BPS relations · Matrix modelsThe book begins with a simple discussion of point particle theory, and uses Feynman path integrals to unify the presentation of superstrings. It has been updated throughout, and three new chapters on M-theory have been added.Prerequisites are an acquaintance with quantum mechanics and relativity.