Blue ring binder of papers, labelled Early 1970’s papers U/24 to U/30 mixed authors. The first is “World-Sheet Supersymmetry and Anomaly Cancellation in the Heterotic String”. --Notice that the date reference on the label is incorrect--.

Three of the 25 binders in the collection contain early drafts of scientific publications by Stephen Hawking, students and closely associated researchers. These were deliberately undated, and would have been circulated among a narrow circle of experts for further edition -or withdrawal-. More finalized versions would become part of Hawking's departments official preprint series.

Preprints are a typical stage in the path of an academic paper towards its publication. They tend to be versions that are ready for peer review, intended for circulation among peers before or during the peer review process. Much actually fruitful scientific communication is done via preprints rather than finalized articles: by the time a scientific paper is officially published, experts in the field have likely already read and commented on earlier versions, and learned from them what is relevant for their own work. Before the 1990s, preprints were generally issued by academic departments, in small print runs of dozens to hundreds; or more informally as photocopies. Many academic departments and research institutions have an officially run preprint series, with (somewhat) standardized numbering and formatting. With the advent first of e-mail and newsgroups, and later online preprint depositories such as ArXiv, the vast majority of circulation has moved online. Since the mid-1990s, printed versions of preprints have become almost symbollic.