Most military studies of British expeditionary warfare in the late eighteenth and early nineteenth centuries focus on the political context, military leadership, regiments, equipment, tactics and manoeuvres, the preparation and the battles themselves, generally without reference to the complex task of transporting the army to the foreign shores. Likewise most naval history books relating to the same period tend to focus on similar issues from the naval perspective including the sea battles, naval leadership, the political and administrative processes, ships and technology. There is a gap in the current literature that this book attempts to fill. The naval and maritime contribution to expeditionary warfare has not been fully appreciated, nor has the mode of conveying troops and sustaining the British army overseas been adequately addressed. The navy's role was essential: by achieving significant victories in famous fleet battles and less well known actions, together with the establishment of effective blockades, it achieved virtual, but not total, control of the oceans, where the main enemy was inclement weather. In addition it provided strong convoy protection for thousands of individual ship voyages, allowing trade to flourish and armies overseas to be sustained. This encouraged the Duke of Wellington to write in September 1813:

Whereas the British launched more than fifty major seaborne expeditions during the Revolutionary and Napoleonic wars involving hundreds of thousands of troop voyages to Africa, India, the West Indies, America and the European mainland from the Baltic to the Mediterranean, the French army generally marched across national boundaries. In contrast to Britain, France launched few major seaborne expeditions involving large numbers of men – the two larger ones being the shipping of the Army of the Orient to Egypt in 1798, when 224 chartered merchantmen convoyed by thirteen ships of the line plus six frigates and other smaller vessels conveyed 24,000 infantry, 4,000 cavalry and 3,000 artillerymen to Aboukir Bay.