This is a reactionary sectarian book promoted by "True Orthodoxy" groups (as of 2021) as a reaction against "ecumenism" and all the ills they see in "World Orthodoxy" as they call it. This book is a large rant & criticism against heretics, Catholics, and liberals, so that the "true church" is only their small band of scattered true believers. They say all the main churches are heretical now, so it's just them and their handful of bishops, digging through old documents to give themselves credibility. This is the tried & true tactic of all cult leaders and sectarians for 2000 years. There are versions of this within Roman Catholicism, Protestantism, Adventists, and Mormonism as well. Who knows how many scattered bands of cults exist around the world, all with their own version of truth & reality.
The Christian Church (the ones obeying the emperors & their hand picked bishops) had always been a living and current being, with obedience towards living bishops who are in communion with leaders of the world. Christianity since the 4th century was nothing but the religious wing of empire, with religion using dogmas as a cover for what they really are: emperor worship & obedience to kings & elites. They never really cared about dogmas & sin, that's just a nice cover for their true purposes of power & control over minds. They've attempted to whitewash history & clean up their act in previous centuries; don't buy it! Constantine is an Orthodox saint, and also a mass murderer & genocidal warlord (par for the course for emperors). The "baptism of Russia" as they call it is likely forgery, but in any case, the Russian emperor was also involved in genocide and forced conversions; another criminal & saint among many in the Orthodox Church.
These "True Orthodox" bishops today want you to believe they are the underground remnant church. Don't buy what these cult leaders are selling you; it's a trap. Breakaway groups & "true churches" are everywhere & this is nothing new.
This book is for "True Orthodox" believers, which is a similar group to the "Traditional Catholics" who are reactionaries, sectarians, and who think they're the "true church." If you ever visit any of these groups, you'll not see holy people, but instead angry reactionaries & cult members who aren't living a holy life (they're largely ignorant as well). Instead it's a bunch of cult leaders & people who want to live in compounds and talk conspiracies about "ecumenism" or "the papists" or whatever theory they have to show how everyone is a heretic, except themselves of course. These groups tend to shelter abusers of all kinds, and able to hide their crimes. Many of these types spin out of control, becoming churches of one or in bunkered compounds in the middle of nowhere (e.g. "Bishop Gregory" in Colorado) with a handful of followers around them. Please don't let yourself get hooked into groups like this, as tempting as it may be to find a "true church." Avoid the numerous bloggers who are the PR wing of these "true" or "traditional" groups. You do not need to isolate yourself & move to a compound in the middle of nowhere; Christians have never done something like this. Stay where you are; nobody needs to move. Live your life where you are and don't feel a need to uproot your life to follow a cult leader or a "true church" somewhere else. Also don't give the bloggers any attention; they're all hustlers and scammers.
I investigated "True Orthodoxy" of various groups, and I ended up rejecting the whole concept and avoiding all these groups, since they're just sects & cults. They point to the past and cherry pick evidence as needed to support their group, but isn't this the tactic used by all sectarians & heretical groups of the past? With mountains of books to choose from, any cult or sect can find evidence to support whatever position they want. Isn't it funny that all the various groups use the same documents, but come to radically different conclusions? They all have the same "Bible" and "Church Fathers" yet they call each other heretics & denounce everyone else. Avoid every single group that dabbles in this stuff. You see these people endlessly bickering over the centuries, each pulling out documents to prove their side, with nobody ever agreeing. Avoid all the churches; they're all liars & are trying to trick you with a mountain of documents.