  Basics of some topics on perturbative and non-perturbative string theory are
reviewed. After a mathematical survey of the Standard Model of particle physics
and GUTs, the bosonic string kinematics for the free case and with interaction
is described. The effective action of the bosonic string and the spectrum is
also discussed. Five perturbative superstring theories and their spectra is
briefly outlined. Calabi-Yau three-fold compactifications of heterotic strings
and their relation to some four-dimensional physics are given. T-duality in
closed and open strings are surveyed. D-brane definition is provided and some
of their properties and applications to brane boxes configurations, in
particular to the cube model are discussed. Finally, non-perturbative issues
like S-duality, M-theory, F-theory and basics of their non-perturbative
Calabi-Yau compactifications are considered.
