Hair removal is a painful pillar of the 21st-century beauty routine. Yet our discomfort pales into insignificance next to the elaborate rituals practiced by our forebears. From the cavemen who used sharply whittled stones to scrape off facial hair to the elegant courtiers of the Elizabethan era who followed the queen’s fondness for a high forehead by applying bandages soaked in ammonia and vinegar to their brows, hair—or the lack thereof—has always been an obsession.

Picture an ancient Egyptian and it’s most likely to be Cleopatra, with her sleek black bob. Underneath it, though, she was bald; like most of her contemporaries, the queen shaved her head and then affixed an immaculate and perfumed wig made from human hair. And it wasn’t just hair on the head that was removed. Bod...