The theme of the unknown is foundational to the plot and characters’ arcs, especially Control’s. Area X’s resistance to comprehensibility, even after numerous expeditions, and its cosmic, uncanny forces provide the sense of unknowability around which both the plot and this main theme revolve. All of the characters’ lives revolve around this great unknown, as Grace explains: “We have been here a long time […]. A very long time. Living with this. Unable to do very much about this. […] it is getting worse. Fewer and fewer journals recovered, and more zombies, as if they have been mind-wiped. And no one in charge has time for us” (39). Part of their struggle comes from the fact that Area X defies the very categories of knowledge that they try to use to understand it. The linguist on the 12th expedition says:

We keep saying ‘it’ […] is like this thing or like that thing. But it isn’t—it is only itself. Whatever it is. Because our minds process information almost solely through analogy and categorization, we are often defeated when presented with something that fits no category and lies outside of the realm of our analogies (113).