Lectures on nongeometric flux compactifications

These notes present a pedagogical review of nongeometric flux compactifications. We begin by reviewing well- known geometric flux compactifications in Type II string theory, and argue that one must include nongeometric `fluxes' in order to have a superpotential which is invariant under T- duality. Additionally, we discuss some elementary aspects of the worldsheet description of nongeometric backgrounds. This review is based on lectures given at the 2007 RTN Winter School at CERN.