Ancient polychromy speaks a language of "the visible" and "the invisible", through signs of pigments, brushstrokes and forms. Another reminder of our classical past, colour is an inherent component of artistic creation, inspiration and imagination. New sophisticated technologies, as well as the development of interdisciplinary studies over these past decades, have stimulated the collection and evaluation of numerous scientific data from in-situ investigation of polychrome and painted documents, and have challenged our understanding of the complexity and function of ancient painting materials and techniques. The present volume is another contribution to the ongoing exploration of the rich history of colour in the classical world; an exploration which builds on previous knowledge and opens up new horizons for a more extended understanding of the aesthetics and meaning of Greek and Roman art. It includes fifteen papers that move from Archaic and Classical Greece to the Hellenistic and Roman periods, and deal with colour on monumental architecture, marble statues and reliefs, wooden and terracotta statuettes, stone sarcophagi, paintings on stone and plaster, and pigments as raw materials.