In any age or in any society, technology is never more than an imperfect attempt by men to overcome obstacles presented by natural forces to the fulfilment of their needs and desires. No technology is perfect. In one way or another, usually in many, it is inefficient or inadequate and does not allow men to achieve the objectives for which they designed it as easily or as completely as they would wish. In these studies I have focused on one such example: the maritime technology of the Mediterranean world from the seventh to sixteenth centuries. Design characteristics of medieval sailing ships and oared merchant galleys, particularly their inadequate upwind performance capabilities, both limited the extent of the commercial sailing seasons and also greatly restricted the choice of routes. Veritable trunk routes or major sea lanes were established, at least partially because of the inadequate technology of ships. In the fifteenth and sixteenth centuries technological improvements mitigated these limitations and restrictions, but not sufficiently to alter traditional patterns of navigation in any marked way. Inadequate sea-keeping abilities, upwind performance capabilities, and load capacities of war galleys limited their range to a functional minimum. The Mediterranean may appear small on a modern world map but medieval and early modern galleys could barely cope with its distances.