In today's media-saturated and hyperconnected society, increasing numbers of people are finding it hard to switch off their overstimulated brains and escape the demands of daily life. We are becoming, it seems, a world of insomniacs. But this condition of perpetual unrest has plagued people for centuries. The roots and effects of insomnia are complex, Eluned Summers-Bremner reveals in this fascinating study, and humans have employed everything...