This article reinterprets and reinvents Prometheus as an archetype of sleeplessness, wakefulness and, finally, watchfulness, for the twenty-first centurya period characterised by proliferating discourses about the so-called epidemic of insomnia suffered in advanced capitalist societies. In the Aeschylean version of the story, as I contend, this mythical hero, who is at once a god and a prophet, is a victim of what might be characterised, with certain qualifications, as sleep deprivation. The article begins by situating Prometheus in mythographic terms, underlining that scholars have tended to overlook the importance of sleeplessness and wakefulness to Zeus's punishment of him. It then proceeds to trace the changes between Hesiod's and the Aeschylean account of Prometheus, with particular attention to matters of crime and punishment. The article goes on to offer a detailed rereading of Prometheus Bound, focusing first on Hermes's threats at the end of the play, which provide an important context for thinking about the penal torture of Prometheus, especially the assault on his sight or vision; and, second, on the torture to which he is subjected by Bia and Kratos at the start of the play, above all the component of it that comprises some form of sleep deprivation. After briefly outlining the importance of sleep deprivation in torture practices of the medieval and early modern periods, the article returns to the classical period and, specifically, the part that remaining awake and hence being conscious of pain plays in an episode in the Odyssey. Finally, in a concluding section, it argues that Prometheus's sleeplessness, though the result of torture, acquires a positive, even heroic value in the Aeschylean play because it is implicitly associated with a state of political vigilance that resists the panoptic surveillance of tyrants. Here, wakefulness is redeemed as watchfulness.