A method (with several variants) of sewing a book during binding: the quires are sewn together by thread carried by two needles working in a figure-eight movement from quire to quire. The boards are then laced onto the loose ends of these threads. Coptic, or unsupported, sewing is unlike sewing on supports, the technique usually employed in the medieval West, in that the quires are not linked by sewing onto cords. Coptic sewing, which provides a more flexible binding and facilitates opening the codex, is generally found in Egyptian and some other Eastern bindings. Among the rare surviving examples from the medieval West is the Stonyhurst, or Cuthbert, Gospel, an Insular Gospel of Saint John made at Monkwearmouth/Jarrow in the late seventh century for placement in the coffin of Saint Cuthbert.
Michelle Brown. Understanding Illuminated Manuscripts (Malibu, CA: J. Paul Getty Museum in association with the British Library, c1994).