Gravitation and Gauge Symmetries sheds light on the connection between the intrinsic structure of gravity and the principle of gauge invariance. The first part of the book gives a systematic account of the structure of gravity as a theory based on spacetime gauge symmetries, discussing basic properties of space, time, and gravity; conformal symmetries; the constrained Hamiltonian of Poincar gauge theory; gravitational energy; and conserved quantities. The second part explores the most promising attempts to build a unified field theory containing gravity. Coverage includes nonlinear field theory, supersymmetry, supergravity, Kaluza-Klein theory, and string theory.