Particle Dark Matter

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.