Direct answer
Objectives follow journal display order. Some depend on your choices; follow the active objective in the game.
Result
Geralt stopped by a certain Novigrad book merchant whose owner recognized him at once. He said someone had left a book with him a long time ago with instructions to give it to Geralt if he ever got the chance. This naturally piqued the witcher's curiosity. Sadly, the book dealer did not know the book's exact present location, only that it had a red cover and that Geralt should look for it in his stacks of dusty tomes and manuscripts.