“What was Tiwanaku?” This question was posed to a select group of scholars that gathered for an intensive two-day conference at the Cotsen Institute of Archaeology at UCLA. For over half a millennium, the megalithic ruins in the highlands of the Andes mountains have stood as proxy for the desires and ambitions of various empires and political agendas; in the last hundred years, scholars have attempted to answer this question by interpreting the shattered remains from a distant preliterate past. The conference pooled the decades of experience of a dozen leading scholars together with the recent field data of junior scholars (published separately in Volumes 2 and 3 of Advances in Titicaca Basin Archaeology). For over half a millennium, the megalithic ruins of Tiwanaku in the highlands of the Andes mountains have stood as proxy for the desires and ambitions of various empires and political agendas; in the last hundred years, scholars have attempted to answer the question “What was Tiwanaku?” by examining these shattered remains from a distant preliterate past. This volume contains twelve papers from senior scholars, whose contributions discuss subjects from the farthest points of the southern Andes, where the iconic artifacts of Tiwanaku appear as offerings to the departed, to the heralded ruins weathered by time and burdened by centuries of interpretation and speculation. Visions of Tiwanaku stays true to its name by providing a platform for each scholar to present an informed view on the nature of this enigmatic place that seems so familiar, yet continues to elude understanding by falling outside our established models for early cities and states.