In October 1950 Ian Doyle was appointed Senior Library Assistant at Durham University Library. He was made Keeper of Rare Books there in 1958, a position he held until 1982. From 1972–85 he was also Reader in Bibliography. In the latter year he took early retirement and thenceforward devoted himself to the many projects to which his scholarship had drawn him. He remained in Durham for the rest of his life, and was a Trustee of the City of Durham Trust.

Ian Doyle was the intellectual heir of Neil Ker, whom he had known since he was a graduate student in the late 1940s. He once told me that he had learned nearly everything he knew about medieval manuscripts from Ker's work. But his own researches led him to focus on the study of Middle English manuscripts, a neglected area before he began. His PhD thesis contained the seeds of a number of his early articles on this subject. His grasp of this field was demonstrated quite early in his career in a series of special lectures at London University in 1966 and in his lectures as Lyell Reader in Bibliography at Oxford in 1967 on ‘Some English Scribes and Scriptoria of the Later Middle Ages’. Neither the thesis nor these series of lectures have been published in their entirety.

A particular focus for Ian Doyle's research was his various studies of individual fifteenth‐ and sixteenth‐century English scribes, including Thomas Betson (The Library, V, 11 (1956), 115–18); William Ebesham (Bulletin of Obituaries the John Rylands Library, 39 (1957), 298–325); the so‐called Hammond scribe (Speculum, 34 (1959), 428–36); John Shirley (Medium Aevum, 30 (1961), 93–101); Stephen Dodesham (in Of the Making of Books: Medieval Manuscripts, their Scribes and Readers: Essays Presented to M. B. Parkes (1997)); William Darker (in Medieval Manuscripts, Their Makers and Users. A Special Issue of Viator in Honor of Richard and Mary Rouse (2011), 199–211) and of the scribe of Bodley 283’ and Durham Cathedral, MS Cosin V II 15 (Journal of the Early Book Society, 9 (2006), 125–29). The most wide‐ranging of these studies was his contribution (in collaboration with the late Malcolm Parkes) to the Neil Ker Festschrift (1978) on ‘The Production of Copies of the Canterbury Tales and the Confessio Amantis in the Early Fifteenth Century’. This paper is still the most significant study of the circulation of vernacular manuscripts of this period. He also published facsimile editions of the Vernon Manuscript (Bodleian Library, MS Eng. poet a. I) in 1987 and of the Thomas Hoccleve autograph manuscripts in 2002 (with John Burrow). His writings about early printed books include his Graham Pollard Lecture, ‘The Printed Books of the Last Monks of Durham’ (The Library, VI, 10 (1988), 203–19).

Ian Doyle's devotion to Durham itself can be seen in the various articles he published on manuscripts in the University's collections and on associated collectors, including Martin Routh (Durham University Journal, 48 (1956)) and Bishop Cosin (Book Collector, 40 (1991)) and on Bamburgh Castle (Book Collector, 8 (1959)). Books produced by religious and monastic orders were a recurrent focus of his interest, which found its most developed expression in his edition of the library catalogues of the English Carthusians for the Corpus of British Medieval Library Catalogues (2003).

A major preoccupation for many years was the catalogue of the medieval manuscripts in Durham University Library, originally undertaken with the late Alan Piper, parts of which already exist in online drafts. It is to be hoped that this can be brought to publication. A volume of his collected papers has also been projected. A volume of essays in his memory is in preparation (there have been two Festschriften); it will include a full list of his writings, extending over more than seventy years.

Ian Doyle's was a long life lived unstintingly and unsparingly in the service of scholarship, not simply though his many publications, extending over more than seventy years, but also through the generosity with which he shared his knowledge and the fruits of his researches with others. Many came to anticipate with gratitude his execrably typed communications, with additions in his distinctive hand, always from a fountain pen, and/or off ‐ prints, frequently enlarged with revisions and addenda, sometimes over running the page. His knowledge was always at the disposal of the enquiring student. He became more comfortable as a lecturer over time, speaking to crowded and attentive audiences, and was a frequent interlocutor in scholarly discussions, always courteous in delivering correction, and almost always right. In later years he was afflicted by difficulties with sight and hear ing, stoically borne. He continued to write (his latest publication appeared in 2017). His last public appearance was at the joint meeting of the John Gower and Early Book Societies in Durham in July 2017 where friends and admirers queued up to show their affection and esteem.

At his death Ian Doyle was the longest serving member of the Council of the Early English Text Society; he was appointed in 1961 and resigned in 2015. His service to the Surtees Society was of similar length: he was a member of the Council from December 1958 until his resignation in June 2012. He was a member of the Advisory Boards of the Index of Middle English Prose and of the Middle English Texts series from their inception, as also the Corpus of British Medieval Library Catalogues.

He received many honours. He was a member of the Comité international de paléographie latine. He was elected a Corresponding Fellow of the Medieval Academy of America in 1991, a Fellow of the British Academy in 1992, and an Honorary Fellow of University College, Durham in 2004. In 2010 he was one of the first two recipients of the Chancellor's Medal of Durham University. He held fellowships from the Leverhulme Trust (1979–80) and the Huntington Library (1980). He was awarded the Sir Israel Gollancz Prize of the British Academy in 1983.