The bulk of the letters printed in this volume are preserved in the archives of Balliol College (Leeper papers, Boxes IA–IIB). The remainder can be found in the Leeper family papers in the State Library of Victoria in Melbourne (MS 1128, Box 3260, folders 11–12). Balliol has acquired photocopies of the Melbourne material (though these are sometimes incomplete and occasionally illegible). A further set of photocopies and the originals of some of Allen's (and Rex's) later papers are in the Churchill Archive Centre in Cambridge (GBR/0014/LEEP).

In preparing the letters, which are handwritten, for publication I have standardized headings, expanded abbreviations, modernized capitalization and the use of numerals, and modified punctuation, though only in cases where the meaning is clear. Obvious errors have been corrected and repetitions deleted. Square brackets, which Allen used frequently, have been replaced by round brackets. Where square brackets appear in the text, they indicate editorial interpolation, including the occasional doubtful reading. Abridgments are indicated by ellipses. Underlinings, the use of block capitals and other embellishments in the originals have also been preserved. Biographical details of all members of the university mentioned in the text (fellows and lecturers as well as undergraduates) are provided in an appendix. Information on other individuals is given in a footnote on their first appearance.