Michelle Magorian: A Little Love Song
Set towards the end of the Second World War and involves a girl called Rose, who is not quite 18 years old. She and her sister are sent away to the country — the first time they've been away from the restrictions of parents, school, etc. She is used to failing at things, and has always felt overshadowed by her beautiful elder sister. Having to deal with a situation where they have to fend for themselves, first experiences of being found attractive to males, and falling in love herself, means that she has to grow up in a very short time — and, in a sense, discovers her true self.
So far it all sounds fairly routine, but what makes it so different it the way it's handled. There are parallels between her own experiences and those of the previous owner of their house, whose diaries she discovers by accident. As the story goes on, there's a sort of counterpoint between the events Rose reads about in the diary and her own experiences and feelings. Also, the similarities and differences between her situation, her sister's, and those of a woman they make friends with (who is in a sort of 'home' for unmarried mothers) — these things give the whole story a richness and a complexity something like (though not to the same extent) what you get in the great 19th century novels. One of those books that leave the events and ideas turning over in your mind for some time after you've finished reading.
It's also quite amazing how the author manages to get to grips with several — shall we say — delicate issues, quite explicitly and without pulling any punches, but in a way that seemed (to me at least) quite appropriate in the context. Not being a parent myself, difficult to judge what age of reader it's aimed at. I'll get my sister to read and decide whether it's appropriate for her children at their age.