Mapping the DarknessNathaniel Kleitman arrived in the US as a penniless teenager who could not speak a word of English. Within a decade, he was pioneering the first ever experiments about how we sleep, and why. He stayed up for 115 hours. He tried moving from a 24 hour day to a 48 hour one. As he became a national sensation, students hungered to join him. His protgs Eugene Aserinsky and William Dement uncovered the mysteries of our sleep cycles. Dements lab assistant,