A book that has a flexible cloth, leather, or vellum cover. In the last quarter of the 18th century and the first quarter of the 19th, limp leather covers were commonly used for books to be carried in the pocket. In the 20th century, the primary use was for cheap, educational, sentimental verse, or devotional books. Also known as limp cloth, limp binding, limp leather, or limp vellum.