Since its excavation in the 1970s, the East Field at Isthmia has been dismissed as a jumble of poorly built houses, marginal to the sanctuary proper. Except for a few small-scale excavations and a handful of studies, the site and its excavation data have sat largely neglected ever since. Now, following a reanalysis of this legacy data and a survey of the standing remains, this volume presents the first comprehensive study of the East Field's architectural and spatial development. Using an innovative method to extract stratigraphic data from outmoded and incomplete sources, the authors disentangle the maze of walls into identifiable structures, setting these within a phased narrative connected to the site's broader history. The results overturn decades of assumptions, revealing substantial structures central to the sanctuary, some possibly corresponding to buildings otherwise known only from inscriptions: the Stoa of Regulus, the Kataluseis of P. Licinius Priscus Iuventianus, and the final site of the Palaimon sanctuary. Additional structures document activity between the 3rd and the 5th centuries CE unattested elsewhere on the site. The East Field at Isthmia offers a radically new understanding of this neglected area of Isthmia and its relation to the sanctuary; along the way, it both encourages archaeologists to revisit long-abandoned excavation data and provides a road map for doing so.