He received a Ph.D. in English from the University of York and specializes in medieval English literature and book history, with several publications in English and Japanese including Death and Purgatory in Middle English Didactic Poetry (1997), Visual Reading (2010), The Canterbury Tales (2019), and The Ultimate Materiality: the Splendour of Western Medieval Manuscripts (2019). Since 1996, he has been involved in a series of projects on the digitization and research of Western rare books, especially medieval manuscripts at Keio University.