Edge gilding is a traditional manual decoration technology used in hardcover book binding in Europe. Gold leaf was applied to the book edge to give it a golden-mirror look. In recent years, domestic restorers are encountering more and more western ancient books that need to be repaired. It is necessary to study this technology and to review related traditional conservation methods. In this paper, we discuss in detail the brief history, main process, tools and materials used and the technical parameters of edge gilding, with the aim of providing a reference for the repair of ancient western books.