For most people the mention of graffiti conjures up notions of subversion, defacement, and underground culture. Yet, the term was coined by classical archaeologists excavating Pompeii in the 19th century and has been embraced by modern street culture: graffiti have been left on natural sites and public monuments for tens of thousands of years. They mark a position in time, a relation to space, and a territorial claim. They are also material displays of individual identity and social interaction. As an effective, socially accepted medium of self-definition, ancient graffiti may be compared to...