The editors of this work first encountered this run of correspondence in the course of their different researches into the history of Orkney and Shetland, John Ballantyne in his work with Brian Smith on Shetland documents, and Peter Anderson in his studies of the two Stewart earls of Orkney. The first of these earls, as Lord Robert Stewart, features prominently in the letters. Peter Anderson had already made basic transcriptions of the letters for research purposes, but it was John Ballantyne who provided independently the rigorous versions which now form the subject of this work.

There are four main sources for this material: in the National Library of Scotland are Advocates’ Manuscripts Adv. Mss 22.3.14 and 54.1.6, and manuscript Ms 1707. In the Roxburghe Muniments in Floors Castle are bundles 1104 and 1634. Those in Adv. Ms 54.1.6 are printed in Mark Napier, Memoirs of John Napier of Merchiston, 63–71, which also contains printed versions of nos. 7, 9 and 10 in the transcription, the original sources for which are unknown.

There are a variety of writers and recipients and none of the letters is in answer to any of the others, though other letters are mentioned, which do not survive. Despite this, and despite the variety of provenances, taken together each surviving epistle contributes to a coherent whole narrative. The run of correspondence, from 1560 to 1582, seems to form an almost continuous chronological sequence. There are gaps in the chronology – in particular, the last in line is separated from the rest by ten years – but most of these are at least partly explicable, with good reasons, other than simple loss, for interruptions in the action. They seem pauses rather than absences, in an ongoing account of a coherent, if contentious, body of affairs. Although of necessity telling only one side of the discussion, each letter tends to contain enough clues to infer the nature of replies and other points of view.

Pivotal to the story is the character of Sir John Bellenden of Auchnoull (1520?–76). He, despite the name of this collection, in fact writes none of the letters, but is rather the recipient of the greater part of them, and is a commanding presence throughout the correspondence, even when he is neither writer nor recipient.