J.R.R. Tolkien contributed "On Translating Beowulf" as a preface entitled "Prefatory Remarks on Prose Translation of 'Beowulf'" to the 1940 edition of C.L. Wrenn's book Beowulf and the Finnesburg Fragment, A Translation into Modern English Prose, which had first been published in 1911 by John R. Clark Hall [REF].
The preface was published under the title "On Translating Beowulf" in 1983 (and in subsequent editions), as one of the essays in The Monsters and the Critics, and Other Essays, also edited by Christopher Tolkien.