How can rock art signal contact between different social groups and cultures? In this special collection of papers for Australian Archaeology, we find several different answers to this question, based on a number of Australian and International case studies first presented at The Second International Contact Rock Art Conference in Darwin, September 2013 and further developed in the years since. In this introductory paper, we set these important depictions in a global context, and explore some of the information that contact rock art offers in studying past, present and emerging societies.