Noughts and Crosses

Sephy and Callum are the best of friends. They grew up together and despite the animosity between their families now, they continue to see each other in secret. But as they grow older and the world encroaches on their friendship, they can deny no longer the big glaring barrier between them: Sephy is a Cross, Callum is a nought. Society, the world, their families, will never accept them.
Sephy is the daughter of Kamal Hadley, a successful and important politician who's manoeuvring his way to the top seat in parliament while his society wife drinks herself to oblivion. She goes to a posh school by chauffeur-driven car and doesn't really understand the discrimination and prejudice the noughts endure.
Callum knows all too well. From being constantly suspected of every possible crime and assumed the worst of, to being denied an education and treated like he's not just stupid but incapable of learning the skills the Crosses have - every day he faces the fact that he's lower than second-class because of one arbitrary fact he has no control over: the colour of his skin.
Yes, Callum is white and he's suffered all his life for it.
Blackman has taken our own history and flipped it around - but it's not an exact mirror-image: the situation of the noughts is far worse in legal terms than what non-whites suffer today in most developed countries (I want to stress the word "legal" here - in Noughts & Crosses, the law doesn't protect the noughts but takes the guilty before proven innocent stance - we have at least moved away from that, though it doesn't change what goes through people's heads still).
Blackman isn't trying to make dark-skinned people look bad and white people sympathetic; she's highlighting how arbitrary and ridiculous racial prejudice is, and how easily it could have been the other way around. She wrecks havoc on the age-old belief that people of one particular skin colour are naturally more intelligent and talented than others - it may not be scientifically supported anymore but the belief is still there, in some places, amongst some people.
Noughts & Crosses is written alternately in the voices of Sephy and Callum, in short chapters that grant the two differing perspectives. There's pain and tension here, and anger - it's a mature book, and doesn't shy away from the worst of human nature. It's well written, with both Sephy and Callum growing older, more mature, more disillusioned. For a book that's not set anywhere in particular, about a world that doesn't literally exist, it's a very real story because it pokes right at the heart of so many of our problems and makes no apologies for forcing us to look at ourselves.
I would have loved this book had I read it as a teenager, I know that for sure. As an adult, I found the chapters a little brief, a bit hurried, a tad too unsubtle. Which would be fine for an adolescent’s attention span?