  The standard framework within which cosmological measurements are confronted
and interpreted nowadays, called Lambda Cold Dark Matter, presents a Universe
dominated by unknown forms of energy and matter.
  My Thesis is devoted to investigate the distribution of dark matter in
galaxies and addresses the fact that the local universe-the small objects that
orbit galaxies and the galaxy cores-turns out to be a marvelous laboratory for
examining the nature of dark matter and the fundamental physics involved in
structure formation and evolution.
  I develop tests, based on mass modeling of rotation curves, for the
validation of dark matter models on galactic scales. These tests have been
applied in analyzing the phenomenology of the cusp vs core controversy, and the
phenomenon of non-Keplerian rotation curves as modification of the laws of
gravity. I further investigate the properties and scaling laws of dark matter
halos.
  My conclusion is that galactic observations provide strong imprints on the
nature of dark matter.
