Several lines of evidence suggest that some of the dark matter may
be non-baryonic: the non-detection of various plausible baryonic
candidates for dark matter inferred, e.g., from galaxy rotation curves
and from cluster of galaxy velocity dispersions,
the need for non-baryonic dark matter for
theoretical models of galaxy formation,
and the large discrepancy between
dynamical measurements implying 
and
the baryon abundance inferred from big bang nucleosynthesis,
. There are a number of well-motivated
dark matter candidates: massive neutrinos, supersymmetric
dark matter and ``invisible'' axions. Many of these dark matter
candidates are potentially detectable by the current generation
of dark matter experiments.