Santa Cruz Island contains a remarkable array of cultural and biological resources and a rich tradition of research across the social and biological sciences and humanities. Given dramatic changes in climate forecast in the coming decades of the Anthropocene, however, many questions remain about the sustainability and future of island ecosystems and cultural resources. Here, we focus on a new interdisciplinary initiative, Island Rediscovery (IR), that was the subject of 2 recent workshops. Drawing on a variety of disciplines and approaches, IR seeks to utilize research on Santa Cruz Island's past and present to help better prepare for the future and plan for forecast change, an approach we call horizon scanning. Our focus is on archaeology, history, and paleobiology, 3 disciplines that offer deep historical perspectives critical to understanding modern ecosystems and preparing for future variability. We outline the potential of deep historical research, offer core questions that can guide future work, and document the need for a large synthetic database and digitization effort. By integrating the historical and biological sciences, the historical ecological approach of IR offers a new framework for managing the resources of the California Islands by providing baselines and context for management, documenting the range of ecological variability through deep time, and helping establish desired future conditions.