* The Complete Tolkien Companion (2006)
* Tolkien:A Biography (2013)
* The World of Tolkiens Sagan om ringen (2014)
* The Fellowship of the Ring:A Reader's Companion (2016)
* The Two Towers:A Reader's Companion (2017)
* The Return of the King:A Reader's Companion (2018)
Artiklar
* "Tolkiens mytologi" (2007)
* "The Lord of the Rings:A Cultural History" (2008)
* "Tolkien och det stora kriget" (2014)
* "The Inklings:A Literary Fellowship" (2015)
* "The Lord of the Rings:A Guide for the Perplexed" (2016)
Övrigt
* Redaktör, J.R.R. Tolkien Encyclopedia:Scholarship and Critical Assessment (2006)
* Producent, The Lord of the Rings:The Return of the King Extended Edition DVD (2004)
* Berättare, The Hobbit ljudbok (2004)
* Gästföreläsare, University of Oxford (2007-2018)
* Gästforskare, University of Leeds (2019-idag)