Book One. We experience the life of Winston Smith through his eyes and some additional narration. Basically, Winston hates the Party, and his life, but there's not much he can do about it...right?
Book Two. It starts with our introduction to Julia and ends with Winston and Julia being caught and taken away by the Thought Police. We knew it was too good to be true. Book Two traces the love life of Winston Smith, in which love is a political act, one of rebellion against the Party.
Book Three. We're with Winston in the torture chambers, a.k.a. the Ministry of Love. Ironic? Yes, yes it is. Here, Winston is physically and psychologically manipulated so that he accepts and loves the Party again. That is, O'Brien reforms Winston the nonconformist into being, well, a conformist. And all it took was a cage of rats.