Geary's primary area of research has been in the early Middle Ages, from circa AD 500 to circa 1100 His scholarship has made significant contributions to a number of areas of medieval social and cultural history, including the cult of relics, literacy and social memory, conflict and dispute resolution, and the formation of ethnic identity in early Europe. He has also published and spoken frequently on the development of medieval history as an academic discipline in Europe and the United States. Over the course of his career, he has taught at Princeton University, the University of Florida, UCLA and the University of Notre Dame. He has also held visiting professorships at several European universities. In 2009, he served as the president of the Medieval Academy of America, and was previously director of the UCLA Center for Medieval and Renaissance Studies and the Medieval Institute at University of Notre Dame. At UCLA from 2005 to 2012, Geary directed a multi-year, international collaborative project sponsored by the Andrew W. Mellon Foundation to produce a computerized image and object database of the Plan of Saint Gall, a medieval architectural drawing of a monastic compound dating from the early ninth century. At the Institute for Advanced Study, Geary worked with an interdisciplinary team of North American and European researchers to apply advanced DNA analysis to early medieval burial remains from Italy and central Europe to help understand population movement and social structures during the so-called "barbarian migrations".
Selected works
Furta Sacra: Thefts of Relics in the Central Middle Ages, Princeton: Princeton University Press, 1978. Revised edition 1991. French translation Le Vol des Reliques. Aubier, 1993. Italian translation Coltura e Pensiero 2000.
"L'humiliation des saints", Annales, E.S.C. 34, pp. 27-42
"Ethnic Identity as a Situational Construct in the Early Middle Ages", Mitteilungen der anthropologischen Gesellschaft in Wien vol. 113 pp. 15-26
"Vivre en conflit dans une France sans état: Typologie des mécanismes de règlement des conflits ", Annales, E.S.C. pp. 1107-1133.
Before France and Germany: The Creation and Transformation of the Merovingian World, Oxford University Press, New York, 1988. French translation, Le monde Mérovingien Flammarion, 1989. German Translation, Die Merowinger, C. H. Beck, 1996 Korean Translation Vistabooks, 1999.
Phantoms of Remembrance: Memory and Oblivion at the end of the first Millennium, Princeton University Press, 1994. French translation Aubier 1996
The Myth of Nations: The Medieval Origins of Europe. Princeton: Princeton University Press, 2002. German Translation: Europäische Völker im frühen Mittelalter. Zur Legende vom Werden der Nationen. Frankfurt: Fischer, 2002.
Women at the Beginning: Origin Myths from the Amazons to the Virgin Mary..
