An endband is a cylindrical band sewn and/or glued to the head and tail of the spine of a book. It is slightly raised above the. An endband along the top edge of the book is called a headband, and one along the bottom edge is called a tailband. Sewn endbands, or 'true' endbands, are sewn into the of the bookblock and perform a mechanical function. They strengthen the sewing of the bookblock and so.