Haynes joined the Brown faculty in 2003. He has written English Literature and Ancient Languages (Oxford, 2003) and The Oxford History of Literary Translation in English , vol. 4: 1790–1900 (Oxford, 2006), which he co-edited with Peter France. Other books include a translation of Heidegger (with Julian Young), an edition of Swinburne, and an historical anthology of English translations of Horace (with D. S. Carne-Ross).
He translated and annotated a collection of essays by Johann Georg Hamann (Cambridge, 2007) and published an essay on him, " 'There is an Idol in the Temple of Learning': Hamann and the History of Philosophy"
He works on the poet Geoffrey Hill, having edited the Collected Critical Writings , (Oxford, 2008), Broken Hierarchies: Poems 1952–2012 (Oxford, 2013), and The Book of Baruch by the Gnostic Justin (Oxford, 2019) and having published several essays on him.
He is the editor and a contributor to vol. 5 (covering the period after 1880) of the multi-authored The Oxford History of the Classical Reception within English Literature (2019).
He has written articles and chapters on varied topics, including the use of Greek and Latin as markers of identity in the Victorian novel, the role of commentarial traditions in producing classic texts, and the history of error.
Over the last decade, he has been preparing, with Ronald Bush, a critical edition of The Pisan Cantos that is now nearing completion. He has written several articles that have spun off from this larger project (on Pound's involvement in a number of translation of the Pisans in the 1950s, and on his unpublished translation from Mencius).
In this period, he took over from Ian Jackson a project identifying the anonymous and pseudonymous contributors to Notes and Queries in the period 1849-1949. He is drafting short biographies of these contributors, with the goal of offering a portrait of the intellectual community behind the journal.
