This article contains plot details from the latest book.
This journal has "The Boy Who Disappeared" written in the corner, but when Sophie goes looking for the journal, the pages are missing. Keefe later helps her realize what it says with a pencil technique.
In Book 2, Exile, Sophie asks Councillor Terik to take her to find a journal she saw in her memories. This journal is found in an exact replica of her house in Mysterium. Sophie retrieves the journal, but the Black Swan had ripped out the pages she needed.