The purpose of this book is to thoroughly prepare the reader for research in string theory at an intermediate level. As such it is not a compendium of results but intended as textbook in the sense that most of the material is organized in a pedagogical and self-contained fashion.
Beyond the basics, a number of more advanced topics are introduced, such as conformal field theory, superstrings and string dualities - the text does not cover applications to black hole physics and cosmology, nor strings theory at finite temperatures.
End-of-chapter references have been added to guide the reader wishing to pursue further studies or to start research in well-defined topics covered by this book."

The purpose of this book is to thoroughly prepare the reader for research in string theory at an intermediate level. As such it is not a compendium of results but intended as textbook in the sense that most of the material is organized in a pedagogical and self-contained fashion. Beyond the basics, a number of more advanced topics are introduced, such as conformal field theory, superstrings and string dualities - the text does not cover applications to black hole physics and cosmology, nor strings theory at finite temperatures. End-of-chapter references have been added to guide the reader wishing to pursue further studies or to start research in well-defined topics covered by this book.

This book provides a self-contained introduction to string theory, at present one of the most exciting and fastest-growing areas in theoretical high-energy physics. Pedagogical in character, it introduces modern techniques and concepts, such as conformal and superconformal field theory, Kac-Moody algebras, etc., stressing their relevance and application to string theory rather than the formal aspects. The reader is led from a basic discussion of the classical bosonic string to the construction of four-dimensional heterotic string models, an area of current research. The so-called covariant lattice construction is discussed in detail. Being conceptually very simple, the book serves to exemplify the relevant features of other methods of arriving at four-dimensional string theories. It is also shown how one derives a low-energy field theory from string theory, thereby making contact with conventional point-particle physics.