This book is not so much about the older iterations and dialects of English themselves as about the development of English into the standard written form, that was finally established 250 years ago or so, and which we use in a relatively unchanged form to this day. The coverage of the language, therefore, consisting mostly of the attitudes toward the language, and the language's differences from its modern and other regional forms, gets much more extensive and detailed for the ages closer to us than ages long past. This is not _quite_ the book I would have wanted to read, because my interests lie more in getting an intimate familiarity with other (older) varieties of English; whereas I found this book to be mostly forward looking, glossing over a lot of the areas that interest me — Old English getting just two chapters with nearly only examples from the chronicles, rather than the wider multifaceted OE corpus. But then this is a book on language, not literature.
That is not to say I did not enjoy the book, to the contrary! I thought it was great fun. It was a very pleasant read that never got boring for the many diverse facsimile reproductions of texts, dosed in bite-sized chucks, with many fun and frequent activities in between, that take you on a seamless journey across time. I suppose I would just have preferred a journey _through_ time, and a bit more explicit information about spoken forms than just written forms and suggestions. I did also quite appreciate the extensivity and rigour of the later chapters in discussing the minute differences, mostly in style and ever so slightly in grammar, in the language since the first establishment of the standard written English in the mid-to-late eighteenth century. I also enjoyed laughing at some of the preposterous, whimsical, and antiquated opinions of the early prescriptive grammarians.
All in all quite a decent and recommendable book.