At the start of the book, there’s an acknowledgement by the author, that goes something like:
This one is for Stephen
The idea for this book was suggested by a boy in a school I was visiting, who asked me to write a book called The Moving Castle.
I wrote down his name, and put it in such a safe place, that I have been unable to find it ever since.
I would like to thank him very much.
Yeah, also a bunch of other details, and the whole plot is way more focused on the war in the movie. In the book it’s more of a backdrop. You should give it a read, it’s worth it :) I also like her other books!