The Mediterranean is one of those seas which is instantly familiar to every European who has had any sort of education or has been on holiday. Its shape, its weather, its food, its waters, its beaches, are all as familiar to any European as his and her own homeland. Not only that, but it has long been one of the most important strategic regions of the world, a region of warfare from its earliest mention in history. Control of the Mediterranean has long been one of the keys to world power – as it still is; and that was one of the keys to the development and maintenance of the British Empire. This sea is the scene of this book, but there are certain additional points which must be made at the start.

The instrument of power used by the British in the Mediterranean was always the Royal Navy. For a century and a half from the defeat of Napoleon that force dominated the sea, and for three centuries before that English, then British, sea power was an intermittent intruder into the complex conflicts and relationships of the sea's other powers. The purpose of this account is therefore to consider the extent, the purpose, and the vicissitudes of British naval power in the Mediterranean. But it is first necessary to understand some of the geography of the sea and to modify to some extent the general understanding of that geography.

The geography of the Mediterranean is complex and intricate; it is an area of bays and gulfs, islands and peninsulas and subordinate seas, narrow passages and straits. It is well over 2000 miles long from west to east, but from north to south it varies from 600 miles between the heel of Italy and the Libyan coast of the Gulf of Sirte, to only sixty miles between eastern Sicily and Cape Bon. It is also much subdivided into distinct sections. Starting from the east there is the Eastern Basin, an open sea with only one island – Cyprus – which stretches from Syria and Egypt to the Sicilian Narrows, where Sicily and Malta and Tunisia compete for strategic importance and to control those narrows.