"Let the barber of Seville shave every man of Seville who does not shave himself.
Who shall shave the barber?"
So my book says that this is self-contradictory. but how?
From my reading of it, it's just that the barber of Seville shaves every man in Seville who doesn't shave themselves. Well the barber doesn't have to shave himself (or he could shave himself). So then someone else can shave the barber along with every man of Seville (and those who do not shave themselves can be shaved twice...)