  Weakly Interacting Massive Particles (WIMPs), are a leading candidate for the
dark matter that is observed to constitute ~25% of the total mass-energy
density of the Universe. The direct detection of relic WIMPs (those produced
during the early moments of the Universe's expansion) is at the forefront of
active research areas in particle astrophysics with a numerous international
experimental collaborations pursuing this goal. This paper presents an overview
of the theoretical and practical considerations common to the design and
operation of direct detection experiments, as well as their unique features and
capabilities.
