In January 1959, famous radio DJ Peter Tripp stayed awake for 200 hours in a glass booth on Times Square, exposing his weakening body and distracted sleepless mind to the public. Tripp's playing with the borderlines of consciousness was a media attraction, but the DJ also served as a guinea pig for scientific research. From the late 19th century on, several experts had tried to explore the world of wakefulness by observing stay-awake-men. With their help, researchers tested methods of measuring (...) alertness, validated and modified theories about sleep, and tried to answer the question of how long and under what circumstances human beings, above all workers and soldiers, were able to stay awake and remain efficient and accountable. By reconstructing the history of the stay-awake-men, this article shows how the perception of “being awake” changed over time and thereby points to the historicity of our very basic notions for describing the states of the human mind. (shrink)