Black Holes in Supergravity and String Theory

We give an elementary introduction to black holes in supergravity and string theory. The focus is on BPS solutions in four- and higher-dimensional supergravity and string theory. Basic ideas and techniques are explained in detail, including exercises with solutions.Comment: 64 pages, based on lectures given at the school of the TMR network 'Quantum aspects of gauge theories, supersymmetry and unification' in Torino, January 26 - February 2, 2000. To be published in Class. Quant. Grav. (Some typos corrected, two references added.