I want to stay away from the obvious question mark as a symbol of the word CURIOUS.
Think about typography, symbols and real life objects that could relate to the word CURIOUS than can be used to create a meaningful logo.
From the logo's I have chosen above I like the simplicity of the concepts in King, CA and Aspenways concepts. I really like the logo's Housecleaner, Spartan stationary, and Writers window as the have found a way to include objects associated with the name in to the logo, whilst keeping it very clean and simple.
I am unsure how much I like the Branddog logo however the concept based around the finger print is an interesting way of associating the logo with the word brand. The Owlbook and Ranch Book logo's are examples of book company logo's I like however I am unsure as to how necessary it is to have a book incorporated into my logo, but food for thought!
It is important to think about the company as more than a notebook business and more as a creative business that involves notebooks at the heart of it's service.
Lastly the design will be embossed on to our books, so take that in to consideration when designing the logo.