Bookmark of Deception Spellbook

[SovelsAtaask]

I'm recruiting for a play by post game on another website, and one of my potential players asked me a question that I'm just not sure what the answer is. Can Bookmarks of Deception be used as spellbooks? While I don't think there's a way to edit the Bookmark after it's created, could it be used to turn any other book into a spellbook with a preset, unchanging list of spells?

[Doc_Maynot]

The Bookmark makes a book appear to be a different one. It could be used to disguise a spellbook, but it's contents are "usually boring or commonplace" and "determined when the bookmark is crafted" (and thus not editable) one could assume that the disguise itself could not be a spellbook. but, if a DM were to allow it to be a spellbook (Probably by factoring in the price of a spellbook's written spells into the bookmark) it would not be mutable after that, thus no more spells could be added in.