In previous games, the notebook was an interactive device where you could link two ideas together to draw conclusions about your findings. In this game, it's just a notebook, a passive list of ideas. When you learn something new, a headline to that effect will pop up on the screen and the item will appear in the notebook, where you can ask people about it when you talk to them.

If you liked the former incarnation of the notebook, take heart; it'll be back for the next two games.