"Anything I have to hide wouldn't be findable by anyone else. And whether the books stay or not depends on the people creating them." There are actually several things that Istredd is hiding, specifically related to Cirilla and his thoughts around her blood and the Singularity. No one gets to see his full notebook where he has pieced together anything related to her, not even Lucifer. Otherwise, all the books he would fill are safe. Technically there is a basement of sorts here, but it's private for him and Yennefer.

His books stick around but not everyone's does. Istredd wouldn't say he 100% understands how it all works but it does, and he would theorize mostly to do with the subconscious and the 'accepted' mindset since otherwise there would never be any locks even possible on domains. This is all even more than his mind can fully comprehend, and that's why he is very fond of it.

"There appear to be several people from that same sphere. My friend Wanda is one of them too, and she has mentioned others." Very interesting to have so many from one place, now that he thinks of it. Then again, there are at least four people from his sphere here. "Apparently they are some kind of group together. Work friends, I suppose?" Istredd hasn't gotten a clear answer on that.