From 27 B.C. to A.D. 117, the Roman dreams of boundless empire began to falter. The very size of their conquests made them hard to manage, and the caesars also had to accept the scale of intractability of the problems posed by the barbarians. The period covered by the book is one of great change and the opening of a new era. For the once mighty Romans this was a time when power was passing; for the barbarians it was the late Iron Age: a time of transition when internal stresses and fear of Roman aggression were creating dangerous shifts in the tribal equilibrium.

Romans and Barbarians sees the clash of cultures from the standpoint of four individuals whose curious fate it was to venture or be sent beyond the outer watchtowers of the Roman empire. They bore witness from the grassy steppe of Europe's southeastern corner; from across the grim Carpathians, towering beyond the Danube; from the fearsome German forest; and from beyond the Firth of Forth in the wilderness of northern-most Britain. Each portrait reveals different aspects of the Sarmatian, German, and Celtic peoples facing the empire's European frontiers. Together these four viewpoints provide a rich portrait of the classical and Iron Age worlds, mutually uncomprehending yet strangely unable to do without each other. The outcome is a skein of violence, tragedy, misadventure, and courage, offering a preview of the cruel but creative forces from whose fusion modern Europe was eventually to emerge.