This is my very first Diana Wynne Jones book, and sadly, her last. I was relieved to find it’s a nice little story, and for something so short and aimed at younger readers, it is also an intelligent, easy read.
Earwig is chosen to move from her orphanage to live with a ‘foster mother’ who turns out to be a witch. Because Earwig isn’t an ordinary child, she isn’t scared by this turn of events, and stipulates that she is to learn from the witch.
Not surprisingly the witch goes back on her word and uses Earwig only for hard work. But I did say that Earwig is no ordinary child, so she sets about arranging her new life to suit.
The witch’s cat is rather nice, and quite useful. The ‘foster father’ however, is not nice at all, and nor are his demons. But, as I mentioned before, Earwig is no ordinary child.
I suppose I wish the witch had been nicer.

I’m so envious of you having all her other books to look forward to!
Ditto to the above comment. Here’s a link to a short and fascinating autobiography Jones wrote for a fan website:
http://www.leemac.freeserve.co.uk/autobiog.htm