Have you already mindread him? If you've already done it, the option disappears. When you mindread him he talks about how he wants to read a certain book, can't remember the name. But one of the bookshelves in the room is interactive, and if you use it it asks you what book you want to read. The book he was thinking is the last option if you have mindread him. If you haven't, then you won't even have the option to choose the book. If successful, a false wall next to the bookshelf will disappear and reveal a secret room.
