CM asks if we can put together a rating system for Christian books. I think this is a good idea, although I think it bears some discussion on the best way to do that.

My thought is something similar to the SJW review of games system might be useful, with zero being the perfect score of containing nothing that would be objectionable to the Christian AND containing genuine and explicit Christian elements. There is a difference, after all, as Misty of Chincoteague is entirely unobjectionable, but it has no Christian content per se.

Let's consider some possible point factors, beginning with those that would likely be more or less acceptable to most Christian parents, but are potentially indicative of religious or ideological problems:
contains no genuine and explicit Christian element +1
exhibits unconventional Christian theology +1
characters demonstrate disrespect for peers or parents +1
an animal or major character dies +1
contains suggestions of physical violence +1

Then there are the elements that will be objectionable to the more conservative families:
contains squishy Disney-style "moral" messages +2
contains direct descriptions of physical violence +2
features indirect sexual themes +2
contains egregious or saintly minority characters +2
features aggressively "pro-science" themes +2
contains euphemistic swearing +2

Followed by those elements to which most parents will not want to expose their children:
contains openly atheist characters +3
contains detailed and gleeful portrayals of physical violence +3
features PG-13 sex scenes +3
advocates left-liberal political or ideological positions +3
contains light and occasional swearing +3
Features emotionally devastating scene +3

And then the completely unacceptable:
contains openly atheist or anti-theist messages +5
mocks Christianity +5
sadistic horror and physical violence +5
features pornographic sex scenes or romanticizes adultery +5
features homosexual and other sexually deviant characters +5
contains a considerable quantity of vulgarities and obscenities +5

Now, it is important to keep in mind that a novel can contain absolutely every element here and still be a Christian novel. What makes a novel Christian or not depends upon its intrinsic recognition that Jesus Christ (or some fictional facsimile therein), is the Lord and Savior of Mankind.

A Throne of Bones scores a lot of points, Book Two will score even more. But they are not books for children; I haven't let my own children read them. Every parent has to draw their own line, but it would certainly be useful to have a large database at Castalia House where books could be rated. For example, The Lord of the Rings would rate about a 5 of 65. A Throne of Bones would rate 30. A Game of Thrones would rate 55. I think anything over 15 should be considered unacceptable to most parents.

There is considerable room for improving the system, and I would welcome suggestions as well as the rating of various books.