  These notes are based on lectures given by Michael Green during Part III of
the Mathematics Tripos (the Certificate for Advanced Study in Mathematics) in
the Spring of 2003. The course provided an introduction to string theory,
focussing on the Bosonic string, but treating the superstring as well. A
background in quantum field theory and general relativity is assumed. Some
background in particle physics, group theory and conformal field theory is
useful, though not essential. A number of appendices on more advanced topics
are also provided, including an introduction to orientifolds in various brane
configurations which helps to populate a relatively sparse part of the
literature.
