Big data have arrived in archaeology, in the form of both large-scale datasets themselves and in the analytics and approaches of data science. Aerial data collected from satellite-, airborne-and UAVmounted sensors have been particularly transformational, allowing us to capture more sites and features, over larger areas, at greater resolution, and in formerly inaccessible landscapes. However, these new means of collecting, processing, and visualizing datasets also present fresh challenges for archaeologists. What kinds of questions are these methods suited to answer, and where do they fall short? How do they articulate with the work of collecting smaller scale and lower resolution data? How are our relationships with "local" communities impacted by working at the scales of entire provinces, nation-states, and continents? This themed issue seeks to foster a conversation about how the unprecedented expansion of archaeological site detection, the globalization of archaeological data structures and databases, and the use of high-resolution aerial datasets are changing both the way archaeologists envision the past and the way we work in the present. In our introduction to the issue, presented here, we outline a series of conceptual and ethical issues posed by big data approaches in archaeology and provide an overview of how the nine essays that comprise this volume each address them.