Somewhere safe, and where my owner was sure to be able to find me.
Well, that's good. Or it would be good, if I were the extremely important notebook. However, I'm not, and it's definitely not anywhere I've looked. Which only means that it's either somewhere I haven't looked, or I missed it. But since I said it's not where I've looked, it's obviously the first option.
edit: Mummy found it! Love you, Mummy! :)