  We have strong evidence on all cosmic scales, from galaxies to the largest
structures ever observed, that there is more matter in the universe than we can
see. Galaxies and clusters would fly apart unless they would be held together
by material which we call dark, because it does not shine in photons. Although
the amount of dark matter and its distribution are fairly well established, we
are clueless regarding its composition. Leading candidates are Weakly
Interacting Massive Particles (WIMPs), which are 'cold' thermal relics of the
Big Bang, ie moving non-relativistically at the time of structure formation.
These particles can be detected via their interaction with nuclei in
deep-underground, low-background detectors. Experiments dedicated to observe
WIMP interactions for the first time reach sensitivities allowing to probe the
parameter space predicted by supersymmetric theories of particle physics.
Current results of high sensitivity direct detection experiments are discussed
and the most promising projects of the future are presented. If a stable new
particle exists at the weak scale, it seems likely to expect a discovery within
this decade.
