Fore-edge-painting refers to a form of representation on the edges of the leaves of a book, which only shows when the book is closed or, in England, when a representation is painted on the fore-edge, the outer edge of a book parallel to the spine, when it is fanned out. Fore-edge painting has been known since the Middle Ages. In 17th-century England, the technique of fore-edge painting experienced an early flowering and was perfected in the latter half of the 18th century by William Edwards (of Halifax). In fore-edge painting of this kind, a narrow strip, at most one millimetre wide, is painted with a landscape or architecture scene so that the motif only shows when the page is fanned out; when the book is closed straight, the painting disappears beneath a layer of gilding or marbling on the edges. A special form of fore-edge painting is decorating the edges with two different pictures, each of which becomes visible depending to which side the page is fanned out.