Edward Johnston Vernon, A Guide to the Anglo-Saxon Tongue: A Grammar after Erasmus Rask, Extracts in Prose and Verse, with Notes etc. for the Use of Learners, and an Appendix (London, 1846).
This is an introduction to Old English published in the mid-nineteenth century, and seems to be the author's only book published. The author's purpose is 'to furnish the learner, if it may be, with a cheaper, easier, more comprehensive, and not less trustworthy guide to this tongue than may hitherto have been within his reach' (p. v). The first six chapters consist of an abbreviated and modified version of the English translation (by Benjamin Thorpe published in 1830) of the Danish philologist Rasmus Rask's Old English grammar, Angelsaksisk sproglaere tilligemed en kort laesebog (1817). Chapter 7, dealing with Old English syntax, is mostly by Vernon himself, and Chapters 8 and 9 are extracts of Old English texts, prose and verse, respectively.
At the very beginning of the preface, Vernon writes that from Old English 'have sprung the greater part of our local and family names, very many of our old, and almost all our provincial words and saying, and fifteen twentieths of what we daily think, and speak, and write', and that 'No Englishman therefore altogether ignorant of Anglo-Saxon can have a thorough knowledge of his own mother-tongue' (p. v). Vernon seems to consider that this would give a good reason for people to learn Old English.
Basically the same idea is also reflected in the following syntactically complex concluding remark of the preface: 'Should this imperfect attempt however, by making the speech of the Anglo-Saxons somewhat easier and more attractive than heretofore to their children, give any of these a better knowledge of the real structure, and true spirit, and a greater love for the power and worth of that tongue, which bids fair one day to overspread the whole earth, some time and labour will not have been spent in vain' (p. viii). English has more or less overspread the whole earth by now, but unfortunately the 'better knowledge' of it has failed to spread widely.
My copy is signed by Vernon himself and includes sporadic corrections in his own hand. He gave this copy to his cousin, William Eccles, in the same year as it was published, which was two years before his death. The book was reprinted after his death in 1850, 1861, 1865, and 1872, but his cousin failed to make the corrections known to the publisher.