Duncan Campbell is a Roman military specialist currently finishing a PhD on Roman siegecraft. He has been widely published in international journals (e.g., 'Bonner Jahrbucher', 'Britannia', 'Historia', 'Zeitschrift fur Papyrologie und Epigraphik'), and is a contributor to Robin Cross's 'Guinness Encyclopedia of Warfare'. Duncan lives near the Antonine Wall in Scotland with his wife and son. Brian Delf began his career working in a London art studio producing artwork for advertising and commercial publications. Since 1972, he has worked as a freelance illustrator on a variety of subjects including natural history, architecture and technical cutaways. Some of his recently illustrated books have been published in over thirty countries. Brian lives and works in Oxfordshire.