Comments of chapter undefined of The Tyrant Gave Me Three Husbands

Who wrote that book Courtney found? Also, why were there so many details left out about the events prior to the failed coup? What is the point of Courtney being brought here at this stage of the novel if she wasn't even able to glean a lot of info about what happened at this stage? Also, is there magic involved in all this? Does Courtney have some hidden power?