detectors using liquid noble elements or cryogenic technologies will advance most rapidly. For the time being, there are clear advantages to proceeding with multiple technologies.

Despite our inability to predict how this field will develop, it is reasonable to expect that by 2010 or so direct detection experiments will reach the $\sim 10^{-9}$ pb level of sensitivity. Roughly speaking, such cross sections are sufficient to test many, if not most, supersymmetric models, as well as many WIMPs candidates in other particle physics frameworks.

Given the rate at which direct dark matter experiments are developing, it is interesting to recognize that such experiments are likely to see their first evidence for WIMPs within the same time frame that the Large Hadron Collider is expected to reveal the presence of the associated physics. In such a scenario, it will be essential to compare the mass of the WIMP observed in each experimental program.

Direct detection experiments can determine the mass of the WIMP by measuring the distribution of the recoil energy, $E_R$ [@Green:2007rb]. This varies with the mass of the WIMP, with a resonance where the WIMP mass equals the target mass. Roughly, one expects , where $m_T$ is the target mass 