I would also agree with the other review that said it's good but not as good as the other two books. I found the part about the parents supporting their daughter very touching but that part is less kid-oriented. The story is good and illustrations too but there is something missing. I think what is missing is actually engaging with the subject matter in that way that Rosie Revere does (with the cheese copter) and Iggy Peck (with the suspension bridge). These other two feel like they bring the story full circle and the ending is satisfying. This one is about questions and although it tries (in the spirit of science) to leave the plot as a question unanswered and to engage with the questions concretely (with the smell), there is something that feels unsatisfying about the question-ending. It feels a bit abstract. We did like it but my children (5, 4 and 2) do not ask to read it as much as they ask to read to the others (which is frequently). All in all though, a good book by a great author!