Mitchell and Robinson's 'A Guide to Old English' is exactly what it claims to be: it smooths the path before the would-be reader of Old English and points out both the obstacles and the areas of interest along the way. It guides the reader through the highways and byways of Old English, and allows him to rapidly gain a reading knowledge of Old English, and some understanding of the workings of the language. Its goal is acquaintance with the tools necessary to decode actual Old English texts, rather than mastery of the language, insofar as composition is a topic omitted altogether. No attempt is made to train the reader to produce Old English.
This guide is not a language textbook in the usual sense of the word. It does not progressively present points of grammar and lists of vocabulary, followed by relevant exercises and translations. Instead, it comprises two parts. The first gives a fairly detailed overview of the grammar and historical context of Old English, whilst the second contains prose and verse texts, accompanied by copious notes, for the reader to attempt. The focus of the first part is not so much the acquisition of paradigms and rules as familiarisation with the general structure of Old English. The section on syntax, very important in Old English, is remarkably comprehensive. The collection of texts in the second part is, in my opinion, well chosen, and representative of the breath of texts in Old English, without dismissing the most famous texts. One particularly useful feature of the guide is its glossary, which contains every word found in the readings, and, for every occurrence of a word in the texts, its part is indicated in the glossary. This simplifies the task of deciphering a text enormously, and obviates the necessity for a separate dictionary.
This sixth edition is not greatly different to the previous editions: minor errors have been corrected, a few small additions on minor points of grammar have been made. The most important change is perhaps the addition of a few texts, e.g., the well-known 'Wulf and Eadwacer', but, all in all, the previous editions were already excellent, and there is no cogent reason to purchase this edition if a previous one is already on hand.
In short, then, Mitchell and Robinson have produced a remarkably usable guide to Old English that is at once instructive and interesting. One could do much worse than to acquire this work if rapid acquisition of reading ability in Old English is desired. As noted by a previous review, the book is not really suited to philologists seeking to understand the history and evolution of English and its place within the Germanic languages. As far as I can tell, this is its single greatest shortcoming, but it doesn't detract much from its purpose. I would heartily recommend this book as an introduction to Old English.