Nine years after the first publication of this book, it is pleasant to record that later works touching on some of the areas it covered have on the whole confirmed or supplemented, rather than overturned the conclusions that I came to. The most noteworthy new work, because closest to the central interests I had in writing the book, is that on the costs of sea transport, begun independently by Douglass North and issuing in a series of articles by him and his collaborator, Gary Walton. They attempt to quantify the decline in shipping costs with some precision, and come to conclusions similar to my own in attributing it in large degree to improved trading organization and to greater safety from plunderers at sea; though I think they underestimate the part played by technical improvement in ships. W. Salisbury has thrown much new light on the problem of measurement of ships’ tonnage in a series of articles in Mariners Mirror, though I still hold the view that measured tonnage was a concept of only very limited importance to the operator of ships. David Syrett's Shipping and the American War, 1775-83(London, 1970) is a very thorough examination of government employment of merchant shipping in wartime, and reinforces my view that this practice was of considerable value to the shipowner in enabling him to opt out of some wartime risks. A new series of volumes on the history of English ports, the first of which, Francis E. Hyde's Liverpool and the Mersey: An Economic History of a Port, 1700-1970 (Newton Abbot, 1971) appeared recently, promises to fill in this part of the background against which the shipping industry worked.

In this book I elected to deal with the English shipping industry as a service industry that carried goods and people by sea. I therefore ignored the fishery, which is an extractive industry that happens to be carried on at sea. Coastal shipping, on the other hand, was omitted because it was already covered very adequately by two well-known works, J.U. Nefs Rise of the British Coal Industry (London, 1932) and T.S. Willan's The English Coasting Trade, 1600- 1750(Manchester, 1938). And so, notwithstanding the fact that at different times during the period covered by this book between a quarter and a half of the tonnage of English-owned ships was engaged in either fishing or coasting, this book is about ships in overseas trade.