2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/9630A brief introduction to the gauge invariant classical and quantum theory of cosmological perturbations is given. The formalism is applied to inflationary Universe models and yields a consistent and unified description of the generation and evolution of fluctuations. A general formula for the amplitude of cosmological perturbations in inflationary cosmology is derived.invited lecture by R.B. at the 37th Yamada Conference `Evolution of the Universe and its Observational Quest', June 7 - 12 1993, 17 pages, 2 figures (available from the authors), BROWN-HET-914; uses phyzzxAstrophysicsHigh Energy Physics - Phenomenologytext