The most fascinating aspect of this novel is the way the narrator in the first part explores the past —our present— dissecting our societies, our complacency, our selfishness, in a striking but not unkind way. The future imagined by the author takes place after the catastrophes, in a much reduced and difficult world, but not the post-apocalyptic setting that's become so boring and cliche, and by framing it this way, McEwan is able to question a lot. Yet, the fundamental question is in the title, what can we know? And what can we do with that?