Service Book of the Holy Orthodox-Catholic Apostolic Church

Isabel Florence Hapgood's compiled and translated service book has been used as a standard English-language Orthodox liturgical reference for well over a century, a documented track record of continued practical use across Russian, Ukrainian, Serbian, Greek, Georgian and Romanian Orthodox practice rather than a claim resting on its original publisher. It is authoritative for the content of these rites as this compilation presents them in translation, not for a scholarly history of how the rites developed or differ between these autocephalous churches, which needs a separate historical source. Use it for the content of a specific Orthodox rite, such as the Panikhida or the funeral service, as this long-used compilation presents it.