Yesterday's Doll, by Cora Taylor (1987), is a perfectly fine and uncomplicated time-travel story from Canada (where it's just The Doll). Meg is recovering from rheumatic fever at her grandmother's house, and is given "the invalid doll" for company--Jessie, the heirloom china doll brought out only when children are sick. Every time Meg sleeps, Jessie takes her back in time, and Meg becomes Morag, traveling west across Canada in a covered-wagon. Jessie seems to want something from her (fixing her with creepy porcelain doll stares), and Meg is compelled to follow where the doll leads....
Meg, once she gets used to the idea, enjoys being Morag--being an only child herself, she enjoys the siblings, and even the prosaic tasks of covered wagon life are interesting (it's very uncomplicated covered-wagon travel--not that challenging for either the participants or the reader). And she likes having two parents who love each other. Though Meg's parents haven't told her, she is pretty certain they are splitting up.
So it's all just fine as we go across the prairie and a calf is born and some berries are picked. But why is the doll so intent on dragging Meg back to the past? Why do Meg's grandma and mother feel the doll wanted something from them when they were little, that they never managed to deliver???
The back cover says: "And then she discovers why Jessie is helping. Meg has to make a choice, one that could change her life forever!"
I read this on the back cover after finishing the book, and was taken aback. This is not the book I read. Sure, as Morag, Meg saves the life of her little sister (very excitingly-an excellent rescue), and dies as a result. This is what really happened; it does not seem as though Meg did anything to change the course of history, although maybe that was what the author had in mind? This is a plot you see lots in time travel, but mostly the author makes it clear that X would have died had not Y travelled back in time and saved her. This author doesn't seem to be suggesting this was the case, though.
Nor is Meg particularly changed as a person, though she does decide to be stoical about the divorce (because she's realized the importance of family?). But she's not particularly sad that Morag has died (she's laughing a few paragraphs after learning about it), so the emotional punch is utterly diluted.
And to make matters more deflating, conclusion-wise, the last time we see Jessie the doll show any signs of life she looks sad and defeated, before the glow of her eyes fades and dies. I have no clue what Jessie's agenda was, but it seems like she failed to achieve it.
Either I am missing something, or the book is missing something....
That being said, Meg's time as Morag is perfectly pleasant time-travelling, and it's a perfectly fine "my parents are getting divorced and I have to cope" story. So if you are an eight or nine year old (especially one who likes the idea of lying around in bed while recovering from illness), you might well love it to bits (lots of Goodreads reviews support me on this), but I don't think I'd give it to anyone much older.