Halting State, by Charles Stross.
It is rare that I find a science fiction book which doesn’t ask me to put my expertise on hold and just “trust in the magic”. Don’t get me wrong, I’m as fond of indulging in pseudo-scientific technobabble as the next geek, but rarely does it make me think more deeply about the real science I do day to day. Halting state is different. It paints a near-future fictional world in which all the technological and social changes seem not only plausible, but likely.