This chapter summarizes the diverse natural environments from which Southeast Mesoamerica’s inhabitants variably drew the resources they used in forging their distinct but interrelated histories. We then review how archaeologists have approached the study of those histories. In particular, we relate the relative lack of interest that researchers exhibited in the area’s ancient inhabitants to trends in anthropological and archaeological theory that pertained throughout much of the twentieth century. Especially important were the efforts of investigators to define the borders of lowland Maya civilization and the relegation of those living beyond those limits in the Southeast to a frontier or periphery whose residents were largely enthralled and dominated by the accomplishments of their lowland Maya neighbors. Ancient Southeast Mesoamerican developments were, thus, understood as pale reflections of, and largely inspired by, events instigated by lowland Maya rulers. The legacy of this approach for our understanding of Southeast Mesoamerica’s Pre-Columbian past is long and pervasive, an issue that is also addressed within this section.