This volume provides the first complete edition of the third and final surviving draft of John Locke's Essay Concerning Human Understanding, dating from 1685, four years before the publication of the Essay itself (December 1689). There is a General Introduction that gives a detailed account of the content and circumstances of composition of this draft, and a Textual Introduction that provides a full description of the manuscript and its history.

J. R. Milton was educated at St John's College, Cambridge, and at Balliol College, Oxford. He taught at Imperial College of Science, Technology and Medicine, and at King's College London, where he was Professor of the History of Philosophy until his retirement in 2014. He has published widely on the history of philosophy in the early modern period, with particular emphasis on the life and writings of John Locke. He is currently General Editor of the Clarendon Edition of the Works of John Locke.

G. A. J. Rogers is Emeritus Professor of the History of Philosophy at Keele University. He was educated at King Edward VI School, Southampton, and the University of Nottingham, before graduate study at St Catherine's College, Oxford, with Gilbert Ryle, Rom Harré, and David Pears, and a PhD at Keele University with Antony Flew. He was appointed lecturer at Keele in 1972 and remained there for his whole career except for two research fellowships at the University of California, Los Angeles. He is the co-editor of Drafts for the Essay Concerning Human Understanding, Volume I: Drafts A and B (1990), for the Clarendon Edition of the Works of John Locke. Drafts A and B, for the Clarendon Edition of the Works of John Locke (1990).