Sheffield presents an ideal location for a study of the structure and performance of a major industrial sector, iron and steel, in the crucial years 1880-1930. The major emphasis of this work is on the structure and strategy of Sheffield's industries which faced increasing competitive constraints in this period. Thus, the response of the firm to change is examined by studying business development both from the point of view of individual firms and from the view of firms as part of a wider business system. The former is achieved by developing a theory of business strategy which aids the understanding of managerial decision making and the internal and external constraints on development. The latter, however, requires a reconstruction of Sheffield's iron and steel industry, which is undertaken for the period 1880-1901, and identifies the structural characteristics of the industry. The retention of a structure of small-scale firms is clearly illustrated, especially in cutlery, and this in turn shaped the the competitive strategy of the firm in relation to market and resource development. For example, the issue of managing the firm's labour input, in terms of a skilled workforce, was a key area for management, and this determined the type of product produced and the market strategy adopted, and ultimately the competitive success of the firm. Furthermore, the study of a key sector of the economy in this period lends itself to a broader analysis of British industrial development, with its emphasis on the alleged conservative response of British businessmen to increasing competitive constraints. On this last issue, there is a need to consider the political response of Sheffield's business community to issues such as protection, state intervention and rationalisation. Thus, a novel component of this work is to incorporate a political economy approach to business history, linking local industrial issues to the wider political environment in the period 1880-1930.