For a given reader in a given cultural context, I believe we can identify three categories of books:
Edifying books tend to make the reader behave effectively for the good of his culture;
Contingent books do not have a clear effect, but may be edifying under some circumstances;
Degenerate books tend to reduce the reader's culturally effective behavior.
Thus a book on Christian pacifism may be edifying for a Christian seminary student, but degenerate for a nominally Christian soldier fighting a war. That same book on Christian pacifism might be degenerate for a Muslim imam who is trying to stay loyal to Islamic pacifism but is at risk of being led aside into heretical Christian mysticism. Fifty Shades of Grey and Pride and Prejudice might be edifying as training material for an aspiring young prostitute/gold-digger, but might be degenerate for everyone else.
Possibly the "contingent" category is the most deserving of analysis. To do a serious analysis, one would need to observe a given book's effects on a large group of readers. This is complicated by the subtleties of immediately observable effects versus long-term, obscure effects. For example, Goldfinger might produce a short-term effect of laziness and self-indulgence in alcohol. The reader imagines James Bond drinking martinis, decides to drink a pitcher of martinis, and passes out in his reading chair. In the long term, however, Goldfinger might subtly indoctrinate the reader into a pro-military stance; the reader might always support pro-war elements in politics because any warmongering politician might seem to be as admirable as James Bond.
I would like to believe that there are some fiction books with no propaganda value, but in fact I believe that all fiction books are necessarily propaganda or advertising of some kind. However, the actual effect of the propaganda may be entirely unsuspected by the publisher and unintended by the writer. For example, the Game of Thrones books might have been intended as a wise sermon on human nature, but in fact, their most vivid images might be the lurid descriptions of food, and thousands of devoted readers might become obese because the books might turn them to lifestyles of gluttony. This would certainly explain the ponderous girth of some Game of Thrones fans.
Fiction obviously can always be interpreted as propaganda, but the threefold distinction applies to nonfiction books. For example, an aspiring student of computer science might always make a point of publicly perusing a very high-level textbook that is actually beyond his skill level. For that student, the high-level textbook is a degenerate book, because it gives him the false satisfaction of appearing clever when in fact he should be writing and debugging programs to increase his skill level.