Prior to reading The Pinhoe Egg, which I just sort of trashed in the previous post, the only book I'd read by Diana Wynne Jones was Howl's Moving Castle, which I did enjoy. So I was interested in the character Chrestomanci in The Pinhoe Egg because I found him to be a Howl-like figure--if you can imagine Howl as a lord-of-the-castle type with a wife and a bunch of kids.
Well, it appears from my minimal reading about the Chrestomanci series that "Chrestomanci" is a title, and I'm guessing that the Chrestomanci of The Pinhoe Egg appears in earlier books in the series as a young person, particularly The Lives of Christopher Chant. (In The Pinhoe Egg Chrestomanci's wife is once referred to as "Lady Chant.") He's a major character in The Pinhoe Egg, but still secondary, if you can follow that. He's not one of the main characters, though he does step forward and solve everything at the end.
I would have liked to have seen more of him and all his various dressing robes, which is what he appears to prefer for daytime wear. (Who can blame him?) So at some point in the future, I'll be looking for a Chrestomanci book that features this particular Chrestomanci.