1984 is a political novel written by G. Orwell.
It is about the totalitarian government. In fact, the author portrays the totalitarian society with an absolute power. He writes his novel before to warn readers of the dangers of this society and the consequences : Government controls the human life by checking their thought to not rebel against the law. Winston Smith, the main character, was going to challenge the limits of the Party's power.
So, there is a psychological manipulation with the telescreen and Big Brother who "watched" them. Citizens can't have sexual desires, the Party controls their thoughts, their feelings.
Moreover, there is a physical control : they watched for any sign of disloyalty, any nervous system. Citizens practice exercises.
Furthermore, the Party controls information and history. Indeed, the past and memories are manipulated. They are unreliable.
Finally, the language is checked by them which means that mind is controled too. The language is very important to human thought.
Everyone who defy the Party is punished with a brutal torture. Moral conviction, emotional loyalty and thought are less powerful than the physical pain.So, the government can control them and the reality. They are able to convincing them that 2 + 2 = 5 : they control all human mind.