Endbands are bands placed at the head and tail of the spine of a book in order to consolidate its ends, strengthen the attachment of the boards, and impede the entry of worms. They consist of cores generally of alum tawed leather, hemp, parchment, or linen cord (with cane and rolled paper also used at later dates) and are usually covered by silk or thread embroidery, with highly varied patterns and techniques. Ideally, the endbands should be tied down in the centers of the quires (often at the same point as the kettle stitch) and their ends laced into the binding boards (see channeling). The identification of different details of endband sewing technique and patterning may help us group books together and assign them to specific production centers.
Michelle Brown, Understanding Illuminated Manuscripts (Malibu, CA: J. Paul Getty Museum in association with the British Library, c1994).