In the first decades of the twentieth century, fiber materials from plants and animals were intensively studied with new analytical techniques, including X-ray crystallography and protein chromatography. Of special interest were protein fibers like keratin and collagen, the main components of wool, silk, and leather. The work was promoted and largely funded by wool growers and the textile industry, who were concerned about the advent of various synthetic fibers and the threat this posed to the future of their businesses. Others saw new opportunities in these developments. The Kaiser-Wilhelm-Institut für Faserchemie in Berlin and the Textile Department at the University of Leeds, the hub of England’s wool economy, became key centers for the new interest in the scientific study of natural fibers. Their research provided important insights into the structure and function of fibrous proteins and is credited with having laid the basis for the study of other biological macromolecules, including DNA, and the rise of molecular biology. Revisiting this history in the context of the Proteins and Fibers project, the study focuses on the commercial and practical concerns that facilitated the interactions between breeders, the textile industry, and scientists, and lay at the heart of the development of the new analytical techniques.