We review basic aspects as well as recent developments in string theory. We discuss the correspondence between superstring theory on curved spaces and gauge theories in flat space-time, the computation of gluon scattering amplitudes using a topological string and the relation between four-dimensional supersymmetric gauge theories and bosonic matrix models. We consider non-critical strings and t...

This elementary introduction to string field theory highlights the features and the limitations of this approach to quantum gravity as it is currently understood. String field theory is a formulation of string theory as a field theory in space-time with an infinite number of massive fields. Although existing constructions of string field theory require expanding around a fixed choice of space-t...