The York-Antwerp Rules occupy a unique position in international maritime law. Unlike the Hague Rules which regulate the law as to the carriage of goods by sea and the various conventions relating to the limitation of shipowners’ liability (to name but two examples), they depend not upon convention, still less upon statute, but upon their voluntary acceptance by the maritime community. Although in a small number of instances1, they have been imported into domestic legislation, the all but universal application of the York-Antwerp Rules in cases of general average has come about by their being incorporated by reference into bills of lading, contracts of affreightment and marine insurance policies. Yet in spite of the purely consensual nature of their application, they have succeeded where other attempts to achieve international uniformity have failed. As was said by Professor Knut Selmer, a by no means sympathetic critic: “It may safely be said that general average is the field of maritime law where the international unification effort has succeeded to the greatest degree.”2 The search for uniformity began with an open letter — now famous — addressed in May, 1860 to the maritime countries of Europe by the National Association for the Promotion of Social Science under the signature of Lord Brougham and the Chairmen of Lloyd’s, the London General Shipowners Society, various Chambers of Commerce and other bodies representing shipping, mercantile and underwriting interests in the United Kingdom. The following sentence reflects the tenor of the letter as a whole and illustrates the aim of its authors:—