This book takes a pedagogical approach to explaining quantum gravity supersymmetry and string
theory in a coherent way. It is aimed at graduate students and researchers in quantum field
theory and high-energy physics.The first part of the book introduces quantum gravity without
requiring previous knowledge of general relativity (GR). The necessary geometrical aspects are
derived afresh leading to explicit general Lagrangians for gravity including that of general
relativity. The quantum aspect of gravitation as described by the graviton is introduced and
perturbative quantum GR is discussed. The Schwinger-DeWitt formalism is developed to compute
the one-loop contribution to the theory and renormalizability aspects of the perturbative
theory are also discussed. This follows by introducing only the very basics of a
non-perturbative background-independent formulation of quantum gravity referred to as loop
quantum gravity which gives rise to a quantization of space.In the second part the author
introduces supersymmetry and its consequences. The generation of superfields is represented in
detail. Supersymmetric generalizations of Maxwell's Theory as well as of Yang-Mills field
theory and of the standard model are worked out. Spontaneous symmetry breaking improvement of
the divergence problem in supersymmetric field theory and its role in the hierarchy problem
are covered. The unification of the fundamental constants in a supersymmetric version of the
standard model are then studied. Geometrical aspects necessary to study supergravity are
developed culminating in the derivation of its full action.The third part introduces string
theory and the analysis of the spectra of the mass (squared) operator associated with the
oscillating strings. The properties of the underlying fields associated with massless
particles encountered in string theory are studied in some detail. Elements of
compactification duality and D-branes are given as well of the generation of vertices and
interactions of strings. In the final sections the author shows how to recover GR and the
Yang-Mills field Theory from string theory.
