Although the books are at the heart of the story, there's a real problem with the world-building around them. You can handwave that the Icelanders, Norwegians, and Finns went back to magic and therefore burned their books, but the Danes and Swedes didn't. The best you can do for the Swedes is that they used books as fuel when it was cold and too dangerous to go searching for firewood, but that doesn't seem to apply to the Danes, who were on their island and presumably not infested with trolls (Bornholm is "safe" not "cleansed"). And then, as tehta points out, even if you suppose that Swedes and Danes did burn their books for fuel or in reaction to the Rash, why aren't books now being scavenged, particularly in Sweden?
They would probably do that (burn), especially books that dealt with subjects they would not think pertinent to survival. Like technology, cookbooks (considering the array of food stuff will be reduced greatly), a lot of fiction.
Part of my head cannon is that books were either scavenged, put in public libraries, or private collections. In areas that are clean. If you look at the Cleaners info on page(s)118-119, It looks like they destroy and not look around. Though I would bet some enterprising individuals would gather up stuff. (Scavenger guild knows the cleanser schedule and grabs first?)
I would think that some libraries would be for reading in the building. That they won't allow the books to leave (Being very valuable, and they would be next to impossible to replace if pilfered.)
For Sweden the scavenger guild could control what comes out of the silent lands (head cannon again and the beginning of the stories I put on A03. I also been putting to story that they are gathering as much info as possible first before selling)
Also, maybe people of Sweden may be like Siv and Torbjörn, not wanting to endanger themselves and willing to let others do the work. After all, Mora is almost modern. Go out there where there are
Monsters?. Sleep on the ground? Not have a shower? Eat field rations?? They have become content with an easier/safer life. What is left of Denmark is also pretty modern. (In my thoughts the Guild did not enter Denmark because to the ghosts and the trouble they have brought Kastrup, and the tank attack, for instance)
For that matter, there's a world-building problem with the whole expedition. Why send it to Silent Denmark? No one would have anticipated that the bridge would collapse, but still, the base can only be supplied by ship or the dangerous and unreliable railroad. Why not send the expedition into Silent Sweden, where, if you did find something really valuable, a second expedition could be easily launched to retrieve it? Or, if the expedition got in trouble somehow (pinned down by trolls, for instance), a rescue mission could be easily mounted from Mora? The sponsors seem to intend to sell the books to Danes, but Swedes are also interested in technology, and anyway, translation would always be an option if the books were in Swedish instead of Danish.
Maybe because they knew Denmark was not picked over ? Maybe they knew the Danes would pay big bucks for old work technology/books especially if it came from
DENMARK's silent lands?
Also, they were on a shoestring budget. I bet a few of those Kroners went to the organizers pockets. (Their salary) That they really were not going to pay for rescue (General Trond used blackmail and not money)
The question of "Why Denmark?" leads me to think that the whole expedition was organized by General Trond to get a specific, unique item that is in Denmark, and the books are just a cover story.
My precccioussssss!