I got this slightly-battered ex-library hardcover from Better World Books, to read for an upcoming book-group.
I found this an interesting take on the "Groundhog Day"/reincarnation concept: here, Ursula Todd's life seems to reboot whenever she dies, and while she herself doesn't remember her previous alternate lives, she does seem to retain some sense of impending doom, enabling her to make different choices. (Early on, her deaths come so soon after her births that the alternate timelines have nothing to do with her own decisions at all, but later on she does seem to have more ability to sway her futures.)
The book as a whole has bookend scenes involving Ursula's attempts to assassinate Hitler; whether or not these are successful we never learn, because Ursula herself does not survive the attempts so we can't see how things turned out. [Due to the trope about the Hitler Time Travel Exemption Act, even if she did kill him it wouldn't have changed the world in the way she hoped.]
Throughout the book, the narrative darts back and forth with each reset, gradually telling us more about the other people in Ursula's life and the ways in which she interacts with them. Some timelines result in fairly significant changes in the lives of characters other than Ursula herself, especially with regard to whether or not certain young girls fall victim to a local murderer - I found those snippets of storyline quite riveting, especially later on, once we realize what's going on and see how close a shave some people have, or realize that a new victim is at risk.
As the number of alternate lives increases, and Ursula's lifespan along with it (for the most part - there are occasional setbacks to an earlier death), she does become aware that something's odd. She still doesn't recall her other lives in detail, but has increasing numbers of deju vu experiences and a growing sense that she really has made various choices before. There are scenes with a psychologist in which she discusses these ideas, and where she begins to get the idea that she might be able to deliberately find ways to alter the future, sparing beloved family members who would otherwise have perished in the war, etc. [Whether her alternate lives are actual resets or are diverging timelines, such that her "changes" do not affect those who died in all the other timelines, is one of many things we - and Ursula - cannot know.]
As the lifeline stories get more intense, especially during WWII and the Blitz, the author plays with us, providing so many ways in which we're sure Ursula will die this time only to have it turn out to be something much, much different. There's also some fun to be had - if a dark, often poignant variety - in guessing whether Ursula's changed actions will help or harm others; while she has only a dim awareness that a certain person shouldn't go to London today, for example, she doesn't know why, and the steps she takes to prevent the "thing that feels wrong" can sometimes make things worse.
I enjoyed following all these threads, working out how the alternate scenes would differ, and wondering whether Ursula will ever be able to complete a normal life and not reboot. (I also wonder whether everyone else has the same experiences, but we're only seeing Ursula's!) And by the end of the book I found myself very pleased with the last set of choices we see her make.
[For another variation on the try-try-again theme, see Replay by Ken Grimwood.]