This is old-school science fiction set in a huge underground “silo,” a vertical city where a remnant of humanity takes shelter from a deadly surface environment, their only view of the outside coming from a set of live camera images shown on wall-size viewscreens on the top level.
The silo is run by an elected mayor and an appointed sheriff, but a lot of power resides with the IT department, a largely autonomous and secretive group of technicians.
The ultimate punishment is expulsion from the silo, something called “cleaning” because the condemned, supplied with steel wool and a protective suit able to keep them alive for a short time, is expected to clean the cameras as his or her final act.
Howey self-published the novel as a series of short e-books, the first (a stand-alone novelette) offered for free. Wool proved very popular and there was talk of a print edition and a film adaptation, though I haven't seen anything on either in a while
I wouldn’t call Wool the best thing since pickles, but it is pretty good. There are two sequels, Shift and Dust, and Howey has written a number of other things. See his website (link) for more.by