  The EROS and MACHO collaborations have reported observations of light curves
of stars in the Large Magellanic Cloud that are compatible with gravitational
microlensing by intervening massive objects, presumably Brown-Dwarf stars. The
OGLE and MACHO teams have also seen similar events in the direction of the
galactic Bulge. Current data are insufficient to decide whether the
Brown-Dwarfs are dark-matter constituents of the non-luminous galactic Halo, or
belong to a more conventional population, such as that of faint stars in the
galactic Spheroid, in its Thin or Thick Disks, or in their possible LMC
counterparts. We discuss in detail how further observations of microlensing
rates, and of the moments of the distribution of event durations, can help
resolve the issue of the Brown-Dwarf location, and eventually provide
information on the mass function of the dark objects.
