The subtitle will help to make clear the scope and focus of this book. All the main aspects of the economic history of steelmaking are touched upon, but no attempt has been made to treat them in equal density. Nor are particular aspects invariably handled with the same fullness at all stages. Thus for instance, technology figures far more prominently in Book I than later. The reasons for such changes of emphasis are, I hope, obvious; save at one point. The developments of the late 'thirties are dealt with on a more insular canvas than those of earlier periods, not because international comparison seemed to become less significant, but because I was insufficiently in touch with the most recent developments overseas to write of them in detail. The whole of the text was in proof and revised before the outbreak of the present war; therefore whenever "the War" is referred to it means the war of 1914-18.
The history of the iron industry before the period covered here has been told so often and so admirably that I have deemed it reasonable to plunge straightway into the controversial discussions of the 'sixties and 'seventies without an introductory preamble. But for readers who may be unfamiliar with the earlier history and with the rudiments of the industry's technique a short description of the iron- and steelmaking processes as they had evolved by 1867 is given in Appendix I. Two maps are included, both drawn by Mr L. D. Lambert. The first is based upon one published by the British Iron and Steel Federation to illustrate the distribution of steelmaking in Britain in 1936. This original has been both amended, and amplified; the insets are new, and a new category of symbols, showing the sites of abandoned (and in most instances dismantled) works, has been introduced, in order to illustrate the changes which have occurred in the location of steelmaking in the last fifty years. No attempt has been made to show these changes for iron-smelting, save where they were significant for steelmaking; it would have