Harpers Lee; some things to take in consideration,

Harper Lee was born in Monroeville, Alabama, a tiny town about halfway between Montgomery and Mobile, where her next-door neighbor and best friend was the pre-pubescent Truman Capote. Her father -- a lawyer and the basis for Atticus Finch in To Kill A Mockingbird -- served in the Alabama legislature from 1927 to 1939. He was reportedly a staunch segregationist until the late 1950s, when the increasing civil rights protests caught his attention and sympathies. Despite popular assumption, the family are not distant descendants of Confederate Genera Robert Lee.

Lee attended three colleges, studied law, and was briefly an exchange student at Oxford, but she received no degrees. By the 1950s she was working as an airline reservations clerk, writing in her free time, until she received a remarkable Christmas present from friends -- a year's wages, without having to work. She argued that they could not afford such generosity, but they insisted that with her talent and a year without distraction, something wonderful would result.

What resulted was To Kill A Mockingbird, published in 1960 and now widely acclaimed as one of the best American novels. It spans three years in the childhood of Jean Louise "Scout" Finch, a young Alabama girl, and her older brother Jem, while their widowed father, small-time attorney Atticus Finch, defends a black man falsely accused of raping a white woman. Deftly sewing these threads into a story larger than its small-town characters and setting, the book spent eighty weeks on the best-seller list, sold 30,000,000 copies, and has been translated into more than forty languages. It won the Pulitzer Prize in 1961, and was adapted into a film in 1962, starring Gregory Peck.

 Taken in : http://www.nndb.com/people/572/000025497/

Also we must take in consideration other important aspects that take place during Harper Lee childhood, such us: the racism of those times, the Economic Depression and the Dust Bowl. All those are factors that influence the author and we can notice them in 'To Kill a Mockingbird'.