How important has the sea been in the development of human history? Very important indeed is the conclusion of this ground-breaking four volume work. The books bring together the world's leading maritime historians, who address the question of what difference the sea has made in relation to around 250 situations ranging from the earliest times to the present. They consider, across the entire world, subjects related to human migration, trade, economic development, warfare, the building of political units including states and empires, the dissemination of ideas, culture and religion, and much more, showing how the sea was crucial to all these aspects of human development. The Sea in History - The Medieval World covers the period from the end of the Roman Empire in the West up to around the year 1500. It demonstrates that for many peoples and states in this period the sea was central to their existence - the Vikings, the Hanse, Venice, Genoa, the Normans - and it shows also how important the sea was for states which are not normally thought of as maritime powers, such as Byzantium, the Crusader states and the Mongol Empire. The book is global in its coverage, including material on East and Southeast Asia, Latin America and the Caribbean and Africa, with particularly interesting material on China's extensive voyages of exploration in the fifteenth century, the role of the Vikings in the early formation of Russia, and on the building of ships, appropriate to local conditions, in different parts of the world. 40 of the contributions are in English; 34 are in French. MICHEL BALARD is Emeritus Professor at the University Paris 1 - Pantheon Sorbonne. CHRISTIAN BUCHET is Professor of Maritime History, Catholic University of Paris, Scientific Director of Oceanides and a member of l'Academie de marine.