Nathaniel 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 protégés Eugene Aserinsky and William Dement uncovered the mysteries of our sleep cycles. Dement's lab assistant, Mary Carskadon, went on to create the first diagnostic tests for sleeping problems. Together, these four figures revolutionised the field of sleep science from extreme self-experimentation to careful clinical work.

As ever more of us lack a good night's rest, Kenneth Miller unveils the lives of those who dedicated their lives to helping us get one.