The process by which a case cover is attached to the bookblock by means of sewing the gatherings to the cover through pairs of holes between which the thread is visible on the spine of the cover, creating one or more longstitch sets, though the threads are often hidden by a secondary cover. Properly speaking, such a structure should be called 'longsewing', but the term longstitch, deriving from the German 'langstich', is so deeply embedded in the literature as to be inextricable. The cover was usually trimmed at the same time as the head, tail and fore-edges of the bookblock were cut, with the result that the cover and the bookblock are of the same height and width, and the cover has neither squares nor turn-ins. Covers can be made with turn-ins, but for this to work, the edges of the bookblock must either be left uncut, or be cut before the book is sewn. Because the cover is attached to the bookblock as the book is sewn, the structure has to be non-adhesive and cannot have any spine linings. The longstitch structure was used in Middle Ages for blank-book or stationery bindings, and the structure was transferred to printed books in Italy as early as the 1480s, as it provided an inexpensive and convenient way to protect and hold together books as they moved through the booktrade to their first owners. Although it is to be presumed that many longstitch bindings will have been rebound by later owners, and the covers therefore lost, the versatility of the structure and its ease of use by readers has meant the many examples have survived. Because of its low cost, it became increasingly associated with inexpensive books such as guide books, popular devotional literature, romances, play-texts and opera libretti, though its ease of opening and flexibility, the consequences of its non-adhesive spine, made it also suitable for music books, as the pages would lie open without trouble at any opening, a necessary virtue for use by a musician. Although very common in Italy, they are also found in the Low Countries and in Germany, in which latter country they seem to have been popular as bindings for student texts. In the Low Countries the structure survived into the twentieth century on almanacs, a testament to the practical virtues of the structure.