Three other articles in this issue of Modern Asian Studies endeavour to trace conceptual changes in the years surrounding the Opium War, and particularly those arising out of works appearing in Chinese on world geography and related Western knowledge. One such work, the Hai-kuo t'u-chih (Illustrated Gazetteer of Maritime Nations), has received mixed reviews since its original publication in 1844. Although read in its various editions by many late Ch'ing modernizers, it provoked sharp criticism on its suggested methods of handling foreign affairs and the outdatedness of its materials. Feng Kuei-fen (1809–74), for example, maintained that ‘only one sentence of Wei Yuan is correct: Learn the strong techniques of the barbarians in order to control them.’ Despite such criticism—generally less totally condemnatory than Feng's—this work not only influenced early modernizers in China but also proved popular among Japanese of the Bakumatsu period, illustrative of its importance in studies on initial East Asian reaction to Western in-trusion. The previous paper dealt with the Hai-kuo t'u-chih's perception of European imperialist expansion in South and South-east Asia. This paper will briefly analyze its significance in a different vein, namely through a more intensive examination of its place in the career and thought of its compiler, Wei Yüan (1794-1857). The acknowledgement that he was less typical than illustrative of his times must accompany the choice of Wei Yüan as a subject for study. A number of the scholargentry minority, he belonged to that even smaller group which rose above mediocrity by serious dedication to the political-intellectual roles traditionally accorded that class. He was specifically untypical in his combination of radical views on Confucian orthodoxy, intense concern for domestic administrative problems and finally relatively enlightened perspectives on the new Western presence in China. Though untypical, this very combination of unique qualities suggests Wei's significance. Tracing his relationship to domestic intellectual and political developments will provide a convenient approach to analyzing, again through this one individual example, the actual interplay between Western intrusion and conceptual change in mid-nineteenth-century China.