Evidence for dark matter can be traced back to very high redshifts, when the Universe was relatively simple. This simplicity motivates physicists to think that dark matter may be another form of stable elementary particles. Among a large variety of choices for dark matter one stands out: weakly interacting massive particles, or WIMPs. They offer a concrete pathway for their discovery, and the last two decades have been spent in their pursuit. I will describe how WIMPs may fit into the structure of modern particle theory, how modern experiments help to narrow the number of theoretical possibilities, and how this pursuit may lead to other serendipitous discoveries of new phenomena beyond standard paradigms.