CIL IV documents the italic inscriptions in the towns of Pompeii, Herculaneum, Stabiae and Oplontis buried in the eruption of Vesuvius in 79 A.D. The new supplement is devoted particularly to the graffiti and dipinti of these towns and includes detailed addenda and corrigenda to the inscriptions already published, numerous new examples discovered since publication of the last supplement, an index and, for the first time, detailed maps.