Historical introduction and overview -- The classical closed bosonic string -- Free bosonic quantum field theory -- Covariant quantization -- Light-cone quantization -- Branes and quantization of open strings -- Open strings and gauge theory -- Supersymmetry in ten dimensions -- Construction of type IIA/B superstrings -- Branes in type II superstring theory -- Construction of heterotic superstrings -- Introductionto conformal field theory -- Modular invariants and orbifolds -- Closed strings on the 3-sphere -- Calabi-Yau spaces -- Calabi-Yau compactifications -- String dualities -- Gauge/string dualities -- AdS/CFT correspondence -- Epilogue: Strings and high energy scatteringAbstract: A concise introduction to string theory explaining central concepts, mathematical tools and recent developments in the field of physics. Covering fundamental concepts including how strings interactwith each other, this book is perfect for students with no prior knowledge as well as scholars from other disciplines.