  Recent breakthroughs in cosmology reveal that a quarter of the Universe is
composed of dark matter, but the microscopic identity of dark matter remains a
deep mystery. I review recent progress in resolving this puzzle, focusing on
two well-motivated classes of dark matter candidates: WIMPs and superWIMPs.
These possibilities have similar motivations: they exist in the same
well-motivated particle physics models, the observed dark matter relic density
emerges naturally, and dark matter particles have mass around 100 GeV, the
energy scale identified as interesting over 70 years ago by Fermi. At the same
time, they have widely varying implications for direct and indirect dark matter
searches, particle colliders, Big Bang nucleosynthesis, the cosmic microwave
background, and halo profiles and structure formation. If WIMPs or superWIMPs
are a significant component of dark matter, we will soon be entering a golden
era in which dark matter will be studied through diverse probes at the
interface of particle physics, astroparticle physics, and cosmology. I outline
a program of dark matter studies for each of these scenarios, and discuss the
prospects for identifying dark matter in the coming years.
