In the past much business history had to depend on published data: annual reports, the information in trade journals and so on. Recent wider access to company records has opened up the fascinating study of decision-taking, revealing the information that was available and the conflicts of opinion out of which came action. The earlier approach was in danger of superficiality; a pitfall of the newer style of work is that details may overwhelm the broad framework, causing themes of general importance to be lost. Though each company pursues its own road, within cognate trades there are shared patterns of development, similar stages of growth and broad coincidences in times of crisis. Cammell Laird had a history of almost 170 years, and at the time of writing has recently foundered. In its heyday it was one of a small group of UK firms with operations spanning steel-making, engineering, ordnance, armour manufacture and shipbuilding, both merchant and naval. Each of these companies became a large, vertically integrated operation, but in their later lives they were dismantled and to a considerable degree merged and reconstructed. Like the other members of this small class, Cammell Laird was a unique variant from a general pattern. Unlike its peers it had for many decades an important, separate, lower-quality line of business, the manufacture of railway track, which involved it in iron-making.

Sources of information and insight into the workings of what was one of the most prominent of UK companies have been many. There is a splendid trade press, which covers the whole range of industrial activities in the country back to the very roots of the firm in the 1820s.