I was wondering if anyone has any information about falsification of history and the annulment of the past in 1984 by Orwell.
In 1984, the main character Winston Smith, plays an employee of the government whose job is to partially annul the past. He receives strips of paper, scraps of paper, documents and pamphlets that are his job to destroy. He is able to read them or look at them, but the telescreens prevent him from recording them or noting anything interesting about them. He seems fully and completely aware of what he is doing as the story is told from a perspective that sees his thoughts. Winston knows that this is wrong morally, but legally according to the laws of this land he does the right thing and destroys the documents that would lead people to believe anything other than what "Big Brother" wants them to think.
The way you phrase your question makes it unclear as to exactly what you are looking for, but 1984 is certainly a storyline that suggests a reconstructing of history which is indeed falsification. The Party destroys any document that would make them sound bad and presents information, even if it is not true, to people that makes the government sound good. Consider the connotation that goes along with "Big Brother". Instead of saying "Mean Dictator" they make this unknown leadership seem warm and inviting.
Consider re-writing your question to elicit the specific response you are looking for.
To me, falsification of history and annulment of the past is one of the major tactics that the Party uses to control the people. They want to control what the people "know" so that they can control what the people think. They want the people to rely solely on them for all their information.
You can see this, for example, in Chapter 4. There, we have our first glimpse of what Winston does for his job. In this chapter, he is completely making up a story about Comrade Ogilvy. This guy never existed, but it is useful for him to exist so that the official history will look like what the Party wants. This sort of thing is seen in many places throughout the book.
To get a better answer, perhaps you could ask a more specific question because this one is really quite vague.