The classical bosonic string.- The quantized bosonic string.- to conformal field theory.- Reparametrization ghosts and BRST quantization.- Global aspects of string perturbation theory and riemann surfaces.- The classical closed fermionic string.- The quantized closed fermionic string.- Spin structures and superstring partition function.- Toroidal compactification of the closed bosonic string — 10-dimensional heterotic string.- Conformal field theory II: Lattices and Kac-Moody algebras.- Conformal field theory III: Superconformal field theory.- Bosonization of the fermionic string — Covariant lattices.- Heterotic strings in ten and four dimensions.- Low energy field theory.