Résumé
I’ll present an introduction to the problem of string theory compactifications with an emphasis on the low energy description of compactifications of type II strings on Calabi-Yau manifolds. In particular, I’ll describe the Kaluza-Klein reduction procedure, basic facts about Calabi-Yau manifolds and why they are important in string theory, effective actions arising in the low energy limit, their moduli spaces, their symmetries and dualities between them. Depending on time, I may also touch the problem of quantum corrections and compactifications with fluxes.