Compilers of any bibliography share the common problems of justifying their selective exercise, defining their field, classifying and cross-referencing. In this bibliography, which deals with theses in maritime history, such problems have been considerable. In consequence, some explanation of the issues involved and the courses of action followed is required. The impetus for the production of this bibliography was two-fold. First and foremost, it arose from the great growth of interest in maritime history over the past quarter-century or so; second, it emanated from a belief that post-graduate theses represent a vast reserve of often little known and under-used knowledge. Both of these observations deserve fuller comment.

The growth of a specific interest in maritime history is but one element of the wider process of specialisation—some would say fragmentation—in history in the post-war era. Desirable or not, this trend is wholly natural. Indeed, it has been characteristic of all fields that advances give rise to specialisation and compartmentalisation of function. The broadening of outlook associated with the development of the social sciences and the growth of historical research at the post-graduate level and beyond have reflected both quantitative and qualitative change. The former is a normal consequence of the growth of higher education, while the latter reflects the tendency toward specialisation inherent in any growth process. Hence, particularly in the last thirty years or so, there has been a veritable explosion of so-called ‘sub-disciplines’ within history, each with its specialist literature, journals, conferences, societies and enthusiastic bands of proselitising supporters. Agricultural, black, econometric, labour, transport, women's, and urban history are but a few of the specialties which have appeared. Maritime history is another. Some of these sub-disciplines, in their focus and approach, represent genuinely new branches of historical study. Most, however, have much older pedigrees and simply represent attempts to consolidate a particular identity for fields of study previously prosecuted within the general ambit of the parent discipline. Indeed, while admitting the quantitative expansion of research in particular fields, it may well be that the most significant trend of the past quarter-century has been the increased public profile of various areas of study rather than the ploughing of hitherto virgin territory.