The system of exchange known as the Kula ring practised in recent times by the Trobriand Islanders has provided a powerful model for anthropology, but its roots in prehistory have remained elusive. Focusing on the island of Woodlark, the author and his team have surveyed the stone monuments which characterise the region and here assign them a date and social context. In them, they see evidence for prehistoric chiefdoms anticipating those studied by Malinowski.