  Several ideas for new physics beyond the standard model may provide particle
candidates for the dark matter in the Galactic halo. The two leading candidates
are an axion and a weakly-interacting massive particle (WIMP), such as the
neutralino in supersymmetric extensions of the standard model. Several
possibilities for detection of such particles are discussed. An assessment of
the relative merits of various WIMP-detection techniques is given. I then
review the prospects for improving our knowledge of the amount, distribution,
and nature of the dark matter in the Universe from future maps of the cosmic
microwave background.
