Deyermond's published output was prodigious – 40 books, written or edited, and almost 200 articles ranging through four centuries of medieval Hispanic literature. He recognised that a comprehensive study of Medieval literature would require several books which exist for studies in English but which were lacking for Spanish. He particularly lamented the lack of complete dictionaries, bibliographies and historical syntheses; as a result he authored the medieval volume for the Ernest Benn History of Spanish Literature (1969), which addressed the lack of an historical synthesis. His volumes of History and Criticism of Spanish Literature (1980 and 1991) carry an in-depth bibliography. A twenty-year research effort culminated in Lost Literature of the Castilian Middle Ages (1995), which Deyermond cited as his favourite work. His last major work was as editor of A Century of British Medieval Studies for the British Academy (2007). Deyermond founded the Medieval Hispanic Research Seminar (1968) at Westfield, which has come to attract scholars from around the world. As part of the Seminar's scope, Deyermond began publishing (1995) the
Publications of the Medieval Hispanic Research Seminar, which carried articles that would be too long for a journal but not book-length. Some sixty volumes were issued, with Deyermond performing nearly all the work. Deyermond participated in founding Tamesis Books (now part of
Boydell & Brewer) and of the series
Research Bibliographies & Checklists (Grant & Cutler), of which he was General Editor. He was General Editor of Critical Guides to Spanish Texts (Grant & Cutler).
Partial list of published works • Alan Deyermond,
A Century of British Medieval Studies (British Academy Centenary Monographs, 2007) • Alan Deyermond, Keith Whinnom,
Jeremy Lawrance,
The Textual History and Authorship of Celestina (Department of Hispanic Studies, Queen Mary, University of London, 2007) • Alan Deyermond, David Graham Pattison, Eric Southworth, Peter Edward Russell ''Mio Cid Studies: 'some Problems of Diplomatic' Fifty Years on'' (Dept. of Hispanic Studies, Queen Mary, University of London, 2002) • Alan Deyermond,
Point of View in the Ballad: The Prisoner, The Lady and the Shepherd and Others (Department of Hispanic Studies, Queen Mary and Westfield College, 1996) • Alan Deyermond,
Historical Literature in Medieval Iberia (Department of Hispanic Studies, Queen Mary and Westfield College, 1996) • Alan Deyermond,
La literatura perdida de la Edad Media castellana: catálogo y estudio, I: Épica y romances, Obras de Referencia, 7 (Salamanca: Ediciones Univ. de Salamanca) • Alan Deyermond,
Historia De La Literatura Espanola : La Edad Media (Letras e ideas: Instrumenta) (Editorial Ariel, 1995) • Alan Deyermond, Jeremy Lawrance (eds),
Letters and Society in Fifteenth-century Spain: Studies Presented to P.E. Russell on His Eightieth Birthday (Dolphin Book Co., 1993) • Alan Deyermond,
Tradiciones y puntos de vista en la ficción sentimental (UNAM, 1993) • Alan Deyermond and Charles Davis (eds.),
Golden Age Spanish Literature: Studies in Honour of John Varey by His Colleagues and Pupils (Westfield College, 1991) • Alan Deyermond,
"Mio Cid" Studies (Támesis Books, 1977) • Alan Deyermond,
The Lost Literature of Medieval Spain: Notes for a Tentative Catalogue (Medieval Research Seminar, Department of Spanish, Westfield College, 1977) • Alan Deyermond,
Lazarillo de Tormes: A Critical Guide (Grant and Cutler, 1975) • Alan Deyermond,
Historia de la literatura española: La edad media (Editorial Ariel, 1973) • Alan Deyermond,
A Literary History of Spain: The Middle Ages (Barnes & Noble, 1971) • Alan Deyermond,
Epic Poetry and the Clergy: Studies on the Mocedades de Rodrigo (Tamesis Books, 1968) • Alan Deyermond,
The Petrarchan Sources of La Celestina (Oxford: Oxford University Press, 1961; with new preface and supplementary bibliography, Greenwood, 1975, ) ==Honours==