Capwell has published several books relating to his speciality. Among them is an authoritative trilogy of works,
Armour of the English Knight 1400–1450 (2015),
Armour of the English Knight 1450–1500 (2021), and
Armour of the English Knight: Continental Armour in England 1435–1500 (2022). Reviewing the first volume in
The English Historical Review,
David Palliser wrote that it "...should revolutionise the study of early fifteenth-century armour, and it is one which document-based historians would neglect to their cost... [He] is that rare scholar, an internationally-renowned expert in his field, who is also a seasoned practitioner of combat in full plate armour, one who can speak with real authority on armour as a practical and functional aspect of medieval life". He has taken part in scientific experiments designed to measure the effectiveness of the
couched lance as a weapon in knightly combat. English sculptor
Henry Moore (1898-1986) was a frequent visitor to the Wallace Collection, and drew inspiration from it. In his later years, he produced several sculptures based on helmets displayed in that museum. In 2019, Capwell and Hannah Higham, in a book titled
The Helmet Heads, analysed those sculptures from the perspective of the original helmets. His television appearances have included
Timewatch: The Greatest Knight (2008,
BBC2, contributor),
The Private Life of a Masterpiece: Caravaggio: The Taking of Christ (2010, BBC2, contributor), ''Metalworks: The Knight's Tale
(2012, BBC4, writer and presenter), Richard III: The New Evidence
(2014, Channel 4, presenter and armour advisor), and A Stitch in Time'' (2018, BBC4, contributor). ==Selected publications==