I am currently reading Galeano's The Open Veins of Latin America which, even if it doesn't seem to deal much with settlement as much as economic exploitation (for now), it is still a pretty sobering telling on the scale in which Native Americans were decimated. I knew it was terrible, but not that it was "From 70 million to 3'5 million" terrible.
Well, best may be a bit of a stretch (nothing can compete against Das Kapital in that regard imho) but it is still a pretty good read, especially to understand the extent of superexploitation and how far back in history it goes.