Western society is obsessed with a good night’s sleep. To get it, we impose strict prebed rituals and regular wake-up times on ourselves and our children, feeling anxious if we toss and turn in the night. But the idea of a perfect sleep practice is relatively new in human history, Benjamin Reiss explains in his new book Wild Nights: How Taming Sleep Created Our Restless World. Until the Industrial Revolution, sleep was social, with family and even strangers sharing beds. People slept in installments throughout the day and night instead of in one straight shot, and sleep schedules varied with the seasons according to light and temperature. Parents sometimes eschewed comfortable mattresses for stiff ones, so their children would be able to adjust to sleep in new places when traveling. It was only with the rise of factory jobs that workers strictly reserved a portion of the nighttime for sleep–leading to the regimented schedule we now observe.
This appears in the March 13, 2017 issue of TIME.