Built around AD 122, Hadrian's Wall was guarded by the Roman army for over three centuries and has left an indelible mark on the landscape of northern Britain. It was a wonder of the ancient world and is a World Heritage Site. Written by a leading archaeologist who has excavated widely on the Wall, this is an authoritative yet accessible treatment of the archaeological evidence. The book explains why the expansion of the Roman empire ground to a halt in remote northern Britain, how the Wall came to be built and the purpose it was intended to serve. It is not a guidebook to the remains, but an introduction to the Wall and the soldiers and civilians, men, women and children, who once peopled the abandoned ruins visited by tourists today.