Editorships
- April 1986 - March 1992:
- co-editor, The Classical Quarterly
- 1992 - :
- co-editor, Cambridge Classical Texts and Commentaries (Cambridge University Press)
- 1992-8:
- ancient philosophy section editor for The Routledge Encyclopedia of Philosophy (London 1998; General Editor Edward Craig), and for updated and enlarged on-line version (2002)
- 1995 - :
- member of the Comitato scientifico e redattivo del Corpus dei papiri filosofici greci e latini (Florence)
- 1998-2007 :
- editor, Oxford Studies in Ancient Philosophy (Oxford University Press), vols 18-34
- 2000- :
- co-editor, Cambridge Classical Studies (Cambridge University Press)