2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/52552These lectures are intended to give a pedagogical introduction to the main current picture of the very early universe. After elementary reviews of general relativity and of the standard Big Bang model, the following subjects are discussed: inflation, the classical relativistic theory of cosmological perturbations and the generation of perturbations from scalar field quantum fluctuations during inflation.44 pages; 3 figures. Lectures delivered at the Cargese School of Physics and Cosmology, Cargese, France, August 2003High Energy Physics - TheoryAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext