Black Maria, by Diana Wynne Jones
Mig, her mother, and her brother Chris go to visit Aunt Maria in her little village of Cranbury-on-Sea. She's really Mig's father's aunt by marriage, but Aunt Maria is very good at guilting people into things. Now that they're there, Mig sees that Maria has no intention of letting them go again. She is the Queen Bee of Cranbury and she expects to get her own way...
Black Maria is really where DWJ lets loose on her opinions about gender roles and equality. Cranbury is a society run by women--completely by women, and it's horrifying. Jones is pointing out rather forcefully that a complete matriarchy would be just as bad as a complete patriarchy. (I always suspect that she had been subjected to one too many enthusiastic lectures about the divine feminine and how wonderful the world was in [fictional] prehistoric times when society was matriarchal and peace-loving.) Under Aunt Maria's reign of manipulation and guilt, these women have forced their husbands to become hen-pecked corporate drones with little will of their own. The children are imprisoned in an orphanage where they are regimented to all be alike. And it's all disguised under a veneer of fluffy sweetness. .
DWJ only barely touches on the further back history of Cranbury, but it seems that centuries ago, the villagers divided up magic, splitting it between male and female. They went on building up more and more rules about the differences between the two sides until each regarded the other as an enemy. Aunt Maria broke the balance completely, imprisoning the leader of the male side and taking over, but she wouldn't have had the chance had there not already been the problem of the split in the first place. The real issue is that every person in Cranbury lives inside a mental prison that forces them to behave according to unreal rules. The men expect to be manipulated; they don't exactly like it, but they can't deal with a woman who doesn't play by the rules they're used to. The women expect the men to be cads, callous and unfeeling, and when a man comes along who wants to be honest and loving, they imprison him.
Because of this, Mig and Chris--who want to work together--keep finding themselves being shoved onto sides because of their gender. Chris treats Mig with suspicion because she's a girl, and Mig is horrified to find that she is expected to submit to being groomed for queendom. Too many of their supposed allies are too enmeshed in the rules to be able to defeat Maria. It takes four people who simply refuse to play by those false rules at all to break the pattern and free Cranbury.
DWJ grew up in the 1940s and 50s and did have a hard time with being a girl. Remember that her parents were (to put it mildly) neglectful, and it sounds as though they often parented by stereotypes--girls could not be heroes of stories, they were supposed to keep house. DWJ talked about what a relief it was to find a few girl heroes in stories (Britomart, for example) who won by doing things, rather than by dying. But it seems to me that she had personal experience and difficulty with both sides; she grew up in a patriarchal society that didn't want to let her do the things she wanted to do, but on the other hand, she clearly had a visceral horror about older, motherly, queenly figures. I think she may have been more truly worried about women in positions of unchecked power. The only answer, clearly, is men and women working together with honesty and respect, as equals.
I suppose this is probably DWJ's most overtly message-y book; she's not normally this way. It's good enough that you don't mind.
Note that this novel is titled Aunt Maria in the US, which makes sense because we don't have the cultural meaning attached to the term "Black Maria." But I bought my copy in the UK, and I think the title is a zillion times better if you do know what a Black Maria is (in US idiom, it's a paddy wagon--a locked van for transporting prisoners). Also, I'm pretty sure it should be pronounced the way that Americans would spell Mariah.