This study is centred on the Cornish manorial estates of the Duchy of Cornwall in the later Middle Ages, and has been compiled from a very full and hitherto neglected series of records, the completeness of which is perhaps unique for a lay estate. Most aspects of the history of the estates have been recorded and those which differed from other regions of England have been stressed. In order to place the Duchy estates within their regional context Dr Hatcher has studied a wide range of documents and produced a mass of new evidence concerning tin-mining, fishing, trade, towns and local industry in Cornwall and Devon. He shows, for example, that agricultural prosperity in later medieval Cornwall followed an exceptional course, and was determined by a series of interconnected changes within the regional economy, with a much less direct and immediate causal link than is commonly assumed between declining population after 1349 and agricultural recession. The intimate connexions between agriculture. and industry and commerce are additionally emphasized by the manifold business interests of leading Duchy tenants.