  After a short introduction on particle candidates for dark matter within
possible extensions of the standard model, we concentrate on Weakly Interacting
Massive Particles, and on one of their most interesting physical realizations:
the neutralino. We analyze how detectability of relic neutralinos by direct and
indirect means is related to their local and cosmological densities; we use
simple general arguments to discusss different scenarios where relic
neutralinos make up the dominant bulk of dark matter or only a small fraction
of it. Our general arguments are further corroborated by specific numerical
results. We show to which extent the present experiments of direct searches for
WIMPs, when interpreted in terms of relic neutralinos, probe interesting
regions of the supersymmetric parameter space. Our analysis is performed in a
number of different supersymmetric schemes.
