Permanent Rose -- Hilary McKay
Permanent Rose picks up a month or two after Indigo's Star left off. The Casson family is (mostly) as happily chaotic as usual with a few exceptions: Caddy isn't so sure that she wants to marry darling Michael, Saffy is stonily determined to dig into the past and find her biological father, and Rose is devastated because Tom (a friend from the States) hasn't called or written since leaving England. She's also become a petty thief and she's annoyed that David the ex-bully has decided that Indigo is his new best friend.
I can't recommend this series highly enough. Hilary McKay is the only author I know of that writes bits like this:
Rose had recently taken to wishing people were dead. At that moment the longing for David to be dead was so intense it made her dizzy. However, it had no effect at all on David. He remained inconveniently alive.
And this:
One of the things that had emerged during the huge noisy conversation the night before was the fact that (not for the first time) Rose had wandered off into town all by herself. And all of Rose's family except Rose agreed that nine years old was much too young for such behavior.
("But I am not nine!" Rose had protested, and very nearly fooled them. Until they remembered she was eight.)
And:
Rose had read one book in her life, and when she had finished it (dragged though it by her father in an effort to educate her), she had read no more. And in her opinion books were for those unable to entertain themselves in any other way. For those who could not draw, who had no ears, who had no one to whom they might speak, who could not switch on a television or walk out of a room or stare out of a window or daydream or suck their knees, these people, she thought, might possibly be able to find a use for a book. Someone stuck in an empty concrete cell with nothing they could use to write on the walls might be grateful for a book, admitted Rose, although even then if they had any imagination, they would use the pages to manufacture paper boats and planes. Therefore, she had not hoped for much in the way of entertainment when she had asked Indigo to read a bit, but even so, she had not expected quite such utter rubbish.
After that, do I really need to explain why I love her so much? She's just ornery, independent Permanent Rose. I can't imagine anyone not loving her.