This thesis addresses two key issues in current rock art research, the first theoretical, the second exemplary. Researchers often write of rock art regions without according the concept sufficient theoretical consideration. Instead, this thesis argues that rock art regions are more usefully defined by the presence and absence of ethnographically informed motifs than by aesthetics.The argument is supported by reference to two understudied rock art regions: the Texas Trans-Pecos, United States of America, and Mpumalanga Province, South Africa. The parallels between the two regions are enlightening: both are cultural 'crossroads' with complex histories of migrations, group interactions, and colonial settlements. Both provide archaeological evidence of hunter-gatherer, herder, and farming peoples. Moreover, both regions are adjacent to other, better-known rock art corpuses that have been explicated using ethnographic analogy and other anthropological approaches.Using these heuristic tools, some of the motivations and meanings behind the production and consumption of rock art in the Trans-Pecos and Mpumalanga are explained. The most effective method for understanding the significance of the motifs Á many of which are also found in the neighbouring regions Á is to focus on ritualism, embodiment, and shamanistic belief in supernatural potency and a tiered cosmos. In Mpumalanga, analysis concentrated on images in 49 hunter-gatherer San (Bushman) rock art sites in and around Kruger National Park. In Texas, it focused on interactions between indigenous hunter-gatherer groups and colonisers from Europe, from Mesoamerica, and from the Plains to the north, using a total of 44 rock art sites as manifestations of indigenous ideologies.Because rock art sites are implicated in cultural identity formation, the lack of theoretically informed presentation perpetuates misleading stereotypes of rock art and the indigenous people who made it. This thesis shows, to the contrary, that the presentation of rock art can and does change people's attitudes towards the past.