“Living in a Culture of the Past” is a microhistorical study of a dossier of fifty-one cuneiform texts written or owned by Iqīšā, son of Ištar-šum-ereš, of the Ekur-zakir clan. Iqīšā lived and worked in the southern Mesopotamian city of Uruk in the late fourth century BCE, during the transition from the end of Achaemenid dominion in the region to the rise of the Hellenistic successor kingdoms. Following the example of theorist of microhistory Carlo Ginzburg, this dissertation reconstructs Iqīšā's particular perspective on the complex, contradictory time in which he lived. As a member of Uruk's urban elite, Iqīšā was deeply invested in the preservation of the privileged status of his class under a new regime. As a teacher of young scribes, Iqīšā endeavored to pass on and preserve essential elements of cuneiform culture and ensure its vibrancy. As a priest of the Rēš temple, Iqīšā balanced the continuation of tradition with intellectual experimentation and innovation. My analysis of Iqīšā's dossier demonstrates the complexity and diversity of Hellenistic Babylonia, the continued vibrancy of cuneiform culture in the late period of Mesopotamian history, the importance of regional differences to our understanding of the transition between the Achaemenid and Seleukid regimes, and the possibilities that new methodologies open up for the history of the ancient Middle East.