This paper discusses large-scale but gradual changes in the subject of holography that have only recently become readily observable. Presenting an analysis of publications in holography over the past half century, the paper illustrates and discusses the evolving shape of the subject. Over 40,000 international information sources have been recorded, including some 20,000 papers, 10,000 conference presentations, 7,000 patents, 1,000 books, nearly as many theses and at least 500 exhibitions. This statistical and sociological approach is combined with the identification of specific factors – notably the role of individuals, conferences, proof-of-concept demonstrations and exhibitions – to suggest that the development of holography has been unusually contingent on a variety of intellectual and social influences. The paper situates these observations about holography and holographers in the context of a wider discussion about the styles, purposes and difficulties of historical writing on technological subjects. It further suggests that this ongoing process of both recording and reconstructing technological history can be aided by identification of sources sometimes overlooked or undervalued by practitioners: unpublished archival materials such as private file collections; business records; accounts of unsuccessful activities; and, by no means least, anecdotal accounts inter-linked between participants.