Dan Spencer is an expert in late medieval warfare, particularly on the subjects of gunpowder artillery and castles. He has experience of writing for both an academic and popular audience, which includes conveying cutting edge scholarly research in a format accessible to non-historians. He has written a number of articles in academic journals as well as co-authoring, The Agincourt Companion (Carlton Books Limited, 2015). He is the main contributor to the www.agincourt600.com website and co-designed the Future Learn open access online course - 'Agincourt 1415: Myth and Reality'. His knowledge of castles and warfare has also been enhanced by his experience of teaching the subject to undergraduate and international students at the University of Southampton.