Holding off the Future: Margaret Haddix, Escape From Memory (New York: Simon and Schuster, 2003).
There is no way to avoid spoilers on this one so I hope you are all sitting comfortably and don't have any large objects to hand. I hate being the target of missiles (I got hit by a grapefruit last night--not sure if it was criticism).
Kira Landon has grown up in a small town in Ohio as an all American girl. Her hair is a bit darker than everyone else's, her mother a bit odd and disinclined to take part in town life. Then one day her friends hypnotize her as a joke, and she retreives odd memories of being carried through a war zone, by a woman not her mother.
Confronting her mother leads to her mother disappearing, to be replaced by Aunt Memory who tells her that Mom is in danger and that she, Kyra, must go to a town called Chryse to rescue her. Kira leaves with Aunt Memory and finds herself in a town in California that is a replica of its Ukranian original. The inhabitants of Chryse are memorizers, committed to an oral culture in which memory and remembering are everything. But things don't feel right, Kira feels she is being set up to be some sort of messiah. Luckily for her, her smarter friend Lynne has stowed away in her luggage, and between them they are able to work out what is going on and to manipulate Aunt Memory into taking them (but not Kira's mother) back to Ohio.
At stake is a system of uploading memories (and personalities) and overlaying them onto others. Kira's parents' turn out to have invented this. Kira's mother turns out to be her aunt, but in an interesting twist, is actually the body of her mother with her aunt's personality overlaid on top.
Haddix's novels for children frequently sit on the very edge of sf and I think this is another case. Although the premise is brilliantly sfnal--someone works out how to upload personalities) -- it actually plays very little part in the "present day" of the plot. I've been teaching Crime Writing this semester, and if we invert Todorov's idea that in the crime narrative there are two stories told, of the past and of the present,then in the the thriller we can think in terms of two stories as the past (there is usually a crime) the present and a (possible) future. The new tech is absolutely of an isolated past-story and a possible-future-story. It is hardly of now at all (although it is convenient for Kira to be able to access her parents' memories directly rather than from the usual diary). And the trajectory of the story is that of the thriller, it is about holding off the future, holding off the consequences of the new tech.
At the end of the novel Kira sits beside her catatonic mother/aunt, with the personality disks beside her, and waits for her to wake and decide who she wants to be. There is an sf novel here, but it is beyond the covers of the book.