England's relationship with the sea in the later middle ages has been unjustly neglected, a gap which this volume seeks to fill. The physical fact of the kingdom's insularity made the seas around England fundamentally important to its development within the British Isles and in relation to mainland Europe. At times they acted as barriers; but they also, and more often, served as highways of exchange, transport and communication, and it is this aspect which the essays collected here emphasise. Mindful that the exploitation of the sea required specialist technology and personnel, and that England's maritime frontiers raised serious issues of jurisdiction, security, and international diplomacy, the chapters explore several key roles performed by the sea during the period c.1200-c.1500. Foremost among them is war: the infrastructure, logistics, politics, and personnel of English seaborne expeditions are assessed, most notably for the period of the Hundred Years War. What emerges from this is a demonstration of the sophisticated, but not infallible, methods of raising and using ships, men and material for war in a period before England possessed a permanent navy. The second major facet of England's relationship with the sea was the generation of wealth: this is addressed in its own right and as an intrinsic aspect of warfare and piracy.