Theory and phenomenology of type I strings and m-theory

The physical motivations and the basic construction rules for type I strings and M-theory compactifications are reviewed in the light of recent developments. The first part of this review contains the basic theoretical ingredients needed for building four-dimensional supersymmetric models, models with broken supersymmetry, and for computing low-energy actions and quantum corrections to these. The second part contains some phenomenological applications to brane world scenarios with low values of the string scale and large extra dimensions.