Sea of Glass
This isn't the first one I've read that plays with the idea of the government restricting the number of children a family can have. And it's not the first one to show a group of kids bonding together in a home run by the powers-that-be to combat abuse and their own confinement. But this is definitely the first one in which the battered, raped, orphaned-by-the-state kid winds up, through a lifetime of his own research, agreeing with those in charge and actively working for them right up through the end of the book.
I think SoG will stick with me in same way that The Sheep Look Up has, though it is more sf and less likely. Over and over in these latter day dystopias, the idea crops up that we need to cut back on population to the point that mass killings becomes the answer. Will that happen? Could be, in the fullness of time. I can't imagine feeling that it's moral even then, though.
There's just so much death in this novel, from characters we know and grow to feel close to up through the nameless, faceless masses. And, in the end, is death actually life? Does it save the world, or is it all just pain for the sake of pain? Almost every destructive or horrific action in the book is taken for what the perpetrator considers a positive reason. Revenge for a friend. To prevent wholescale war. In search of affection. Do the means justify the ends? That's not a question that I have the philosophical credentials to answer, in the large scale.
final thought: One of the better ones I've read in the past year and a half, and one I'll pass on to others.