As any liturgist worth their salt will tell you, having the text of a liturgy is only a part of understanding a past liturgical experience or a liturgical tradition. As one who works with thousand year old liturgies, I have to continually hold in mind that a liturgy is not a text—it’s an experience, and that what I see on a page before me is not necessarily determinative for what may have occured in an actual embodied space. Thus, historical liturgists are always on the look out for customaries, documents that flesh out how a set of liturgies were actually performed in a certain time and place.
Even when we have a customary, though, that’s rarely the end of the discussion. A customary may help us visualize the liturguy better but, again, it’s still a document and not an event. And customaries have their purposes too, describing not only what does happen but—quite often—what the author wants to happen or wishes to happen. Indeed, some customaries can be polemical treatises that attempt to implant in the reader’s mind one particular model that is to supplant all others. (For instance, whenever I need a chuckle, I read through the section entitled “Of Practices Not Recommended” in Galley’s Ceremonies of the Eucharist… I should also mentioned that it’s been argued that the seminal treatise of Hippolytus upon which so much of the modern Liturgical Renewal movement is based is far more polemical and prescriptive than descriptive of early Roman worship.)
As an American interested in the history of Anglican worship, I have no lived experience of worship with the 1662 BCP. Certainly I can pick it up and read through it; the text and rubrics are clear enough for most anyone to follow. There are, however, ambiguities and options explicit in the text, and anyone who knows the wide vaariety of Anglican theologies, practices, and churchmanship realizes that there must have been differences in how various groups worked with or resolved these ambiguities. Without lived experience, we fall back on customaries.
Principle customaries for the 1662 with which I am familiar are three (Please note, these are intended as introductions, not as authoritative commentary; feel free to add notes or other items in the comments!):
The Directorium Anglicanum: First published in 1858 by John Purchas, a leading Ritualist, this is a guide to the 1662 that seems well suited to larger churches with a traditional architectural format. It argues that the rubrics of the early prayer books expect a certain amount of liturgical knowledge lacking in the priests of its day and thus seeks to “put the Priest of the nineteenth century on a par with the Priest of the sixteenth century as to ritual knowledge. An html copy of the First Edition can be found here at Project Canterbury’s liturgical archive. New to me (and what prompted this post) is my discovery of a PDF version of the Second Revised Edition of 1865. (A read of the preface to the second edition gives you a sense of the battles in the midst of the Tractarian (Oxford Movement’s) growing momentum. A catholic work that harkens back to Sarum uses as well as mentioning (then) contemporary Roman uses, I consider it moderately high. The first edition makes none of the references to the saints or the Blessed Virgin found in Roman or Later Anglican works.
Ritual Notes: This is probably the best known of the catholic customaries. Originally published in 1894, it has gone on to 11 editions. There is no better way to stimulate a discussion that will consume many hours and much gin than to ask a group of Anglo-Catholics which edition is the best. Current answers to “the best” tend to bounce between the 11th, 9th, and 8th reflecting how one feels about recent (20th-21st century) changes to the Roman liturgy and the degree to which current Roman practice should either be followed or rejected. (Brief sample here…). Currently some Continuing Churches sell the 11th, the Western Rite Antiochene Orthodox sells the 9th, and the first edition in html format can be found here. (An 11th edition sits on my shelf though I’d put a 9th edition next to it if I had one…)
The Parson’s Handbook [English Use]: Probably the least known in America, this is the work of “Blessed” Pearcy Dearmer, the classic example of an Anglo-Catholic Socialist. (Wikipedia entry on the Handbook is here.) While the first two references have—as far as I can determine—some links to living traditions, this work attempts to go back to as exclusively Sarum Use as possible. As such it is particularly susceptible to accusations of antiquarianism and “museum” liturgy. Nevertheless, this work did establish a following and while it might have been a novelty when it was first published it is now a living movement of some weight in England. The handbook went into no less than 13 editions in rather rapid succession. (I don’t know if there are arguments over preferred editions here…) Dearmer first penned the work just seven years after ordination; he made revisions as he worked out the implications of his program by implementing it in his own parish. The First Edition in html format is at Project Canterbury; the Forth Edition as a PDF may be found here.