  The recent observations of galaxy and dark matter clumpy distributions have
provided new elements to the understating of the problem of cosmological
structure formation. The strong clumpiness characterizing galaxy structures
seems to be present in the overall mass distribution and its relation to the
highly isotropic Cosmic Microwave Background Radiation represents a fundamental
problem. The extension of structures, the formation of power-law correlations
characterizing the strongly clustered regime and the relation between dark and
visible matter are the key problems both from an observational and a
theoretical point of view. We discuss recent progresses in the studies of
structure formation by using concepts and methods of statistical physics.
