Introduction to Superstring Theory

String theory has been the leading candidate for a theory that consistently unifies all fundamental forces of nature, including gravity. In a sense, the theory predicts gravity and gauge symmetry around flat space. Moreover, the theory is UV-finite. The elementary objects are one-dimensional strings whose vibration modes should correspond to the usual elementary particles. At distances large with respect to the size of the strings, the low-energy excitations can be described by an effective field theory. Thus, contact can be established with quantum field theory, which turned out to be successful in describing the dynamics of the real world at low energy. In this book, the author explains the basic structure of string theory, its predictions and problems.