The photographer William Green has produced a lovely sequence of shots of Tokyo taxi drivers asleep in their cars. "It seems to be a culture where, unlike the West, you're allowed to be asleep in public," says Green. "In the UK that's only OK if you're pissed or really knackered."
In an essay focused on present day sleep-aiding gadgets, Patricia Marx alludes to historical efforts to induce slumber: "The ancient Romans smeared mouse fat onto the soles of their feet, and the Lunesta of the Dark Ages was a smoothie made from the gall of castrated boars. Charles Dickens apparently believed it was necessary to position himself in the precise center of a bed that faced exactly north, while the Glasgow Herald advised the worried wakeful to lather up their hair with yellow soap before bedtime, wrap their heads in napkins, rinse in the morning, and repeat every night for two weeks. In 1879, a Canadian medical journal recommended hemlock. Presumably, no repeating was required."