Answer:
Gatsby mostly lies to Nick about his life. Fitzgerald chooses to tell the story of Jay Gatz so that readers won't misjudge Gatsby.
Explanation:
"The Great Gatsby" is a novel by author F. Scott Fitzgerald. The narrator is Nick, who suddenly finds himself caught between the lies and affairs of rich people. Nick is befriended by Jay Gatsby, a mysterious millionaire who lives next door to him. It turns out that Gatsby is in love with a married woman, Daisy, who happens to be Nick's cousin.
Everyone talks about Gatsby, but no one knows who he is, where he is from, how he became rich. Some people even say he is murderer. In Chapter 4, Gatsby tells his own version of his life story to Nick. He talks of being the heir of his parents fortune, of having traveled the word, of having attended Oxford. He even has a photo and a war medal to prove his tales true. Nick believes him, but Gatsby is lying. The only slightly truthful part is having gone to Oxford. He did go, but only for 5 months, since it was an opportunity given to some army officials.
In Chapter 6, Nick decides to tell the real story about Gatsby. Chronologically speaking, that is not the moment when Nick finds out about it. That would be in Chapter 8, after a car accident involving Gatsby and Daisy. But Nick chooses to tell the story sooner, because he cares too much about Gatsby, and doesn't want his character to be misjudged. As Nick says, "He told me all this very much later, but I've put it down here with the idea of exploding those first wild rumors about his antecedents, which weren't even faintly true."
In reality, Gatsby was born very poor on a farm in North Dakota, his real name being James Gatz. He never appreciated being poor and, being very ambitious, did try to climb the social ladder by befriending a millionaire. When the millionaire died, Gatsby was indeed his heir, but he never got to receive the money because of the man's family. After meeting Daisy, Gatsby's ambitions grew bigger. His dreams were now too urgent for him to wait for a miracle or an honest opportunity, so he became a criminal, selling fake bonds and illegal alcohol.
