Some four thousand years ago, the cultivation of silkworms began, the practice spreading to the far reaches of civilization. With it came a growing obsession with unlocking silk’s secrets to understand how the strongest biological material ever known could be harnessed. Explorers and scientists, including groundbreaking women who pushed the boundaries of societal expectations, dedicated—even sacrificed—their lives to investigate the anatomy of silk-producing animals. They endured unbelievable hardships to discover and collect new specimens, leading them to the moths of China, Indonesia, and India; the spiders of Argentina, Paraguay, and Madagascar; and the mollusks of the Mediterranean. Rich with the complex connections between human and nonhuman worlds, not only peers into the past but also reveals the fiber’s impact today, inspiring new technologies across the fashion, military, and medical fields, and shows its untapped potential to pioneer a more sustainable future. The culmination of author and biologist Aarathi Prasad’s own lifelong passion and grounded in years of research and writing, is an intoxicating read that provides an essential illumination of nature’s most glamourous thread.