David Abulafia begins with the earliest of seafaring societies - the Polynesians of the Pacific, the possessors of intuitive navigational skills, long before the invention of the compass, who by the first century were trading between their far-flung islands. By the seventh century, trading routes stretched from the coasts of Arabia and Africa to southern China and Japan, bringing together the Indian Ocean and the western Pacific, linking together half the world through the international spice trade. In the Atlantic, centuries before the little kingdom of Portugal carved out its powerful, seaborne colonial empire, many peoples sought new lands across the sea - the Bretons, the Frisians and, most notably, the Vikings, now known to be the first Europeans to reach North America. As Portuguese supremacy dwindled in the late sixteenth century, the Spanish, the Dutch and then the British each successively ruled the waves.

Following merchants, explorers, pirates, cartographers and travellers in their quests for spices, gold, ivory, slaves, lands for settlement and knowledge of what lay beyond, David Abulafia has created an extraordinary narrative of humanity and the oceans. Besides its grand narratives, The Boundless Sea explores the lesser known maritime enterprises of Denmark, Sweden, Oman, Sri Vijaya and many others. And today, as plastic refuse covers thousands of square miles of the waters, and once exotic trading cities and outposts are replaced by vast, mechanized container ports, he asks - what next for our oceans and our world?