Since retiring in 2002 he has continued his researches into Greek palaeography, textual criticism and the history of classical scholarship. In the series of Oxford Classical Texts his edition of Aristophanes appeared in 2007, and a new edition of Herodotus followed in 2015. An interest in the Italian Renaissance resulted in an edition of the prefaces to Aldus Manutius' publication of Greek authors (2016).
Another substantial piece of work was a contribution to the study of the famous manuscript of Archimedes, which was sold at auction in New York in 1998 for $2,000,000; the results of a collaboration lasting ten years and involving experts in various fields appeared in The Archimedes palimpsest (Cambridge University Press 2011), which was described by the reviewer in the TLS as “the most beautiful book produced in this century”. Current projects include work on one cache of palimpsest manuscripts found at St. Catherine's monastery on Sinai and a new edition of an important Byzantine text, Photius' Biblicotheca.