His research concerns early modern European history, with special focus on Portugal, its overseas empire, and Catholic history. He has written Journey to the East: The Jesuit Mission to China, 1579-1724 (Belknap/Harvard, 2007) and has edited a volume of essays entitled Portuguese Colonial Cities in the Early Modern World (Ashgate, 2008). His articles discuss Jesuit missionary activity in Asia, as well as the development of European overseas empires in the sixteenth and seventeenth centuries. Current research projects include a study of the calamitous seventeenth century in the Portuguese empire in Asia, a translation of the sermons of the famed Portuguese Jesuit preacher António Vieira, and an examination of religious life in the city of Lisbon in the second half of the sixteenth century.