• Parish Church Treasures, The Nation's Greatest Art Collection, Bloomsbury, October 2015.
  • The English Castle, 1066-1640, Yale University Press, April 2011.
  • God's House at Ewelme. Life, art and devotion in a medieval almshouse, Ashgate Publishing, 2001.Winner of Royal Historical Society’s Whitfield Prize, 2001.

Articles and essays

  • ‘The Age of Worship’, in the BBC book of David Dimbleby’s Seven Ages of Britain, Hodder and Stoughton, 2009, pp.62-89
  • ‘Lady Anne Clifford and the architectural pursuit of nobility’ in ed. K. Hearn and L. Hulse, Lady Anne Clifford: Culture, Patronage and Gender in 17th-century Britain, Yorkshire Archaeological Society Occasional Paper, no.7, 2009, pp.73-86
  • ‘Patronage, function and display: the secular world, 650-1650’, in ed. T. Ayers, The History of British Art, vol.1, Yale and Tate Britain 2008, pp.115-35
  • Ashby de la Zouch and Kirby Muxloe Castles, English Heritage Red Guide, 2007
  • Warkworth Castle and Hermitage, English Heritage Red Guide, 2006
  • ‘The Great Tower of Rochester Castle’, in eds. T. Ayers and Tim Tatton-Brown, Medieval Art, Architecture and Archaeology at Rochester, British Archaeological Association Rochester Conference Transactions, xxviii, 2006, pp.265-99
  • ‘The Aerary Porch and its influence on late medieval English vaulting’, in ed. N. Saul, St George’s Chapel Windsor in the Fourteenth Century, Woodbridge 2005, pp.165-202
  • ‘Herstmonceux Castle, Sussex’, Burlington Magazine, cxlvi, no.1217, August 2004, pp.516-25
  • Muchelney Abbey, Somerset, English Heritage Guidebook, 2004, with Francis Kelly.
  • ‘The Great Tower of Carlisle Castle’, in eds. M. McCarthy and D. Weston Carlisle and Cumbria, Roman, Medieval Art, Architecture and Archaeology British Archaeological Association Carlisle Conference Transactions, xvii, 2004, pp.39-62
  • Essay and catalogue entries in Gothic: Art for England 1400-1547, ed R. Marks and P. Williamson, Victoria and Albert Museum Publications, 2003.
  • 'The architecture of ancestry at the Collegiate Church of St Andrew at Wingfield, Suffolk', in ed. R. Eales and S. Tyas Family and Dynasty in Late Medieval England. Harlaxton Conference Transactions, ix, 2003, pp.156-171
  • Portchester Castle, English Heritage Guidebook, 2003
  • Whitby Abbey, English Heritage Guidebook, 2002 (out of print)
  • Eton College and the Court of Henry VI' in Windsor. Medieval Art and Archaeology. British Archaeological Association Conference Transactions, xxv, 2002, pp.247-63
  • Richmond Castle and St Agatha’s Abbey, Easby, English Heritage Guidebook, 2001
  • ‘The Chantry of Humphrey, Duke of Gloucester’, co-authored with L. Monckton, British Archaeological Association St Albans Conference Transactions, xxiv, 2001, pp. 231-55
  • Bodiam Castle, National Trust Guidebook, 2001
  • 'The siege of Dover 1216-7', Chateau Gaillard Conference Transactions, xix, 2000, pp. 91-102
  • ‘The medieval Palace of Westminster’, Houses of Parliament: History, Art, Architecture, eds. C. and J. Riding, Merrell Publishers, London, 2000, pp. 49-67
  • Scarborough Castle, English Heritage Guidebook, 2000
  • Pevensey Castle, English Heritage Guidebook, 1999
  • 'The lost Chapel of Queen's College, Oxford, and the design of its east window' The Queen's Journal, vii no.2, 1996, pp. 23-33
  • 'A study of the Grotesque 14th-century Sculpture at Adderbury, Bloxham and Hanwell in its architectural context.' Oxoniensia, lx, 1995, pp. 271-332