The City of London was at the centre of a commercial empire, remarkable in its global reach. Britain was the world's banker, and its mercantile marine and overseas investments were among its most significant ‘imperial’ attributes. This remarkable economic system is the subject of a comprehensive study by P.J. Cain and A.G. Hopkins. Now in its second edition, British imperialism, 1688–2000 is an impressively learned book of 739 pages, developed from an influential pair of articles in the Economic History Review, entitled ‘Gentlemanly capitalism and British overseas expansion’, published in 1986 and 1987. In British imperialism, the authors propose a large-scale simplification and hold a strong interpretative line through a long period of time (although 1688 to 1850 is dealt with in a forty-page ‘prospective’).