I pursue a cross-cultural comparative perspective that puts Greco-Roman history in a broader context. Only comparisons with other civilizations make it possible to distinguish common features from culturally specific or unique characteristics and developments, help us to identify variables that were critical to particular historical outcomes, and allow us to assess the nature of ancient Mediterranean societies within the wider context of pre-modern world history. For these reasons, I am trying to study key institutions cross-culturally, focusing on the interrelated themes of economic development, empire, and slavery. Together with my Stanford colleagues Ian Morris and Richard Saller, I co-edited the Cambridge Economic History of the Greco-Roman World. This project has been complemented by a companion volume on the Roman economy edited by myself. Ian Morris and I were the editors of a volume on the dynamics of ancient empires that had grown out of a series of conferences sponsored by Stanford’s Social Science History Institute. Together with Peter Bang of the University of Copenhagen, I have completed a handbook of state formation in the ancient Near East and Mediterranean, and I edited a general handbook of Roman studies jointly with my colleague Alessandro Barchiesi. In addition, I have launched an international research initiative promoting comparative study of imperial states in the ancient Mediterranean and ancient China that has resulted in a pair of collaborative volumes bringing together experts from different areas. This project has been complemented by a year-long research seminar and a workshop on what I have proposed to call the ‘First Great Divergence’ between eastern and western Eurasia in the second half of the first millennium CE. Starting in 2009, my comparative history initiative has been expanding to encompass a wider range of early empires and draw on the resources of several partner institutions. This has led to a new project, a comprehensive world history of empires to be co-edited with Peter Bang and Chris Bayly. I am also working on theoretical models for the study of ancient empires. In addition, I have co-edited conference volumes on fiscal regimes in early states (with Andrew Monson) and the global history of slavery (with John Bodel).