One of Rome's legions is missing! The disappearance of the Ninth Legion is a mystery that has piqued the interest of historians and archaeologists since the eighteenth century. They knew that it had formed part of the Roman garrison of Britain from the time of the emperor Claudius, but there was no record of its involvement in the great frontier works of the second century. It seemed simply to have disappeared. What had happened to it? Now, archaeologist Duncan B. Campbell follows the trail of research down through the decades in a meticulously documented account. Registering each new item of evidence as it came to light and explaining its significance, he pieces together the unfolding solution to the age-old mystery.