Historians have clearly articulated the ways in which sleeplessness has long been part of the human condition. As an object of medical expertise and public health intervention, however, insomnia is a much more recent invention, having gained its status as a pathology during the 1870s. But while insomnia has attracted considerable and concerted attention from public health authorities allied with sleep medicine specialists, this phenomenon is not well explained by classical medicalization theory, in part because it is the sleepless sufferers, not the medical experts, who typically have the authority to diagnose insomnia. The dynamics of insomnia's history are better described as those of a boundary object, around which concepts and practices of biomedicine and psychology coalesce to frame contemporary notions of self-medicalization and self-experiment.