In the last twenty years, cosmology has become a precision science. Since the COBE era, a wealth of data, along with advances in theoretical interpretation and numerical analysis, provided us with a convincing model of the content and evolution of our Universe. It is now generally
accepted that an early period of inflation produced a nearly homogeneous flat Universe, with small inhomogeneities (of quantum origin!) which can be seen as temperature anisotropies in the cosmic microwave background (CMB), and which grow by gravitational instability to form the large scale structure (LSS) of the Universe.
