Dr Duncan B Campbell is a specialist in Greek and Roman military history. He first became fascinated by Roman archaeology after a childhood visit to Hadrian's Wall. He published his first academic paper in 1984, as an undergraduate at Glasgow University (Scotland), and produced a complete re-assessment of Roman siegecraft for his PhD. He has made some of his research accessible to a wider readership through Osprey's New Vanguard, Elite, and Fortress series, and he is a regular contributor to *Ancient Warfare* magazine. Besides writing occasional academic articles, he is a frequent reviewer for *Bryn Mawr Classical Review*. In his latest book, *The Fate of the Ninth*, he discusses the curious disappearance of Rome's Ninth Legion.