This awsome movie has been created by the artist Hayao Miyazaki. Also creator of Spirited away, and Ponyo on a cliff by the sea
Althought the book of Diana Wynne Jones is a bit diffirent, its still a great movie.
All characters through out the movie have enough room to develop.
Only one thing, the movie end abrubtly.

Can't wait to read Castle in the air (not to be confused with Castle in the sky which is also a Miyazaki movie) which is an appendix of Howl's moving caslte and House of Many Ways