I can remember quite well where Howl's Moving Castle lived on the shelf in the library where I grew up. It was not the first DWJ book I read (that was Witch's Business) but it was one of the early ones. I must have found it right after it was published in 1986. As a result, I practically have it memorized -- I could not tell you how many times I've read it. Even so, I enjoy it anew every time, and I still have new realizations about what's going on. (Though possibly I have the same ones over and over, and just forget! My kids tell me so sometimes.)
When I first met my husband, he had kind of forgotten reading for fun, as a lot of people do in college, and I gave him Howl's Moving Castle to read -- the same copy that is sitting here now, which is a UK edition from Mammoth that my mom got for me on a trip. After we got married, husband and I also took a trip and bought a bunch of DWJ titles at Blackwell's.
This story may not be quite as complex as Hexwood is, but it could still use a diagram, especially of which one was what one and what one was who. Nearly everyone has at least two identities (again) and then there are the bits of people too. I mean, I think the skull was Ben Suliman's, and Prince Justin's head was in the dog spell with Ben's body....but then there's the scarecrow too. Aargh. That guy who draws xkcd has done some quite fancy diagrams of LOTR and other things -- do you suppose he's ever read DWJ?
It seems to me that Howl's Moving Castle plays with some of the same themes as Pride and Prejudice does. Sophie assumes that she knows all about Howl's character, and she doesn't. She takes Martha's prejudiced view of her stepmother Fanny and only at the end does she realize how much she has misjudged not only Fanny, but her two sisters as well. Of course, assuming that we know someone and finding out otherwise is a constant; we all do it all the time. At least, the first part; the latter is probably somewhat rarer and is a salutary lesson in humility!
Diana Wynne Jones passed away eight years ago today, in 2011. She is greatly missed, and it's so nice to be able to have this anniversary every year and talk together about her creations. Thanks, everybody!