1984 by George Orwell (1949)

Somewhere in the Ministry of Truth, a clerk feeds yesterday's newspaper down a brass tube called the memory hole, and the past it recorded simply stops having happened. This is Winston Smith's daily work, and George Orwell built a whole world around the quiet horror of it: a regime that does not merely lie but dissolves the ground on which any lie could be caught, until no fixed fact survives to measure it against. What Winston defends, in a diary he knows will damn him, is something a child could state: that stones are hard, that water is wet, that two and two make four. The novel's terror is watching even that arithmetic put up for negotiation. Read it for the grey, close-walled prose that leaves you nowhere to hide, and for Room 101, where the Party stops wanting your obedience and reaches for something far more intimate. Few books have looked so steadily at what remains of a person once the truth itself is taken away.