The story is told directly by one of the main characters, Scout Finch. This is an example of first person narrative. Scout is an inhabitant of the town of Maycomb and relates the story of a particular period of her life when she was growing up there. The most dramatic event in her narrative is the trial of Tom Robinson which becomes the focus of the book's examination of the theme of racism and other social prejudices. The narration is quite subtle in that it is being told from the point of view of Scout when she is considerably older and is looking back to that earlier time, but we still get all the thoughts and feelings of the young Scout, supplemented by commentary from her older and wiser self. This makes for a fuller, more rounded out perspective overall.
Jean Louise “Scout” Finch is the narrator of To Kill a Mockingbird. She is an adult at the time she narrates the book, but the book is told from her perspective as a young child over a period of years from about six to nine. A first person point of view is used, with an unreliable narrator.
The adult perspective also adds a measure of hindsight to the tale, allowing for a deeper examination of events. (enotes style)
We know that Scout is older because she writes from the perspective of an adult looking back, trying to understand what she saw as a child.
When enough years had gone by to enable us to look back on them, we sometimes discussed the events leading to his accident. (ch 1)
Despite the age of the adult narrator, we still get a child’s perspective on most events. This is what is known as an unreliable narrator, both because a child is narrating and because it is a memory.
Since Scout is so young at the time of the book’s narration, she can describe events with a child’s innocence. During the trial, Scout understands most of what is going on, but not as much as her older brother Jem.
"I think it's okay, Reverend, she doesn't understand it."
I was mortally offended. "I most certainly do, I c'n understand anything you can."
"Aw hush. She doesn't understand it, Reverend, she ain't nine yet." (ch 17)
Scout’s coming of age story allows the reader to get a feel for what life would have been like in the deep south in the Great Depression. Her naïve, blatant, no-holds-barred approach lets the reader into the inner circle, making us feel like a native Maycombian.