A Hunt for Dark Matter: a Tale of Sensitivity and Direction*

We are now in the era of precision cosmology, where we know the age of the Universe, the geometry of space, the total energy density and what types of energy and matter contribute to it. Measurements suggest that ordinary matter, composed of protons and neutrons, is a mere 18% of the gravitational mass in the Universe. The rest is dark, and so far we infer its existence only gravitationally. The goal of detecting and identifying dark matter is arguably one of the most important problems in 21st century science.  We briefly review some of the observational evidence for dark matter, and describe the experimental efforts to detect a signature critical for its discover.