Around 330 B.C., a remarkable man named Pytheas set out from the Greek colony of Massalia (now Marseille) to explore the fabled, terrifying lands of northern Europe—a mysterious, largely conjectural zone that, according to Greek science, was too cold to sustain human life and yet was somehow, they knew, the source of precious commodities such as tin, amber, and gold.

Whether Pytheas headed an expedition or traveled alone, he was the first literate man to visit the British Isles and the coasts of France and Denmark, and there is convincing evidence that he traveled on to Iceland and the edge of the ice-pack—an astonishing voyage at the time. Pytheas’s own account of the journey, titled On the Ocean and published in about 320 B.C., has not survived, though it echoes in the works of ancient historians like Herodotus and Strabo. Their allusions to his voyage represent the beginnings of European history and underscore how much of a pioneer Pytheas was, for Britain remained without further explorers until Julius Caesar and his legions landed there almost 300 years later.

Archaeologist Barry Cunliffe knows perhaps more than anyone about the world through which Pytheas traveled, and he has sifted the archaeological and written records to re-create this staggering journey. Beginning with an invaluable pocket history of early Mediterranean civilization, Cunliffe illuminates what Pytheas would have seen and experienced—the route he likely took to reach first Brittany and then England; the tin-mining and, even then, evidence of ancient cultures he would have witnessed onshore; the challenge of sailing in a skin boat; the magic of amber and the trade routes by which it reached the Mediterranean. In telling this story, Cunliffe has chronicled an essential chapter in the history of civilization.