What were Harper Lee motivations for writing to kill a mockingbird book?

Harper Lee has always claimed that her novel "To Kill a Mockingbird" was not autobiographical. However, there are a number of similarities to Lee's life and the life of Scout and Atticus Finch. Lee's father was a southern lawyer, like Atticus. According to childhood friends, Lee was a tomboy like Scout. And Lee had a special friend like Dill because every summer the boy who would become the celebrated author Truman Capote used to visit. Many believe that Lee was influenced by what influences many writers and that was her own personal experience. In addition, Lee wanted to say something about the civil rights movement which was at its height in 1960 when the book was published. Even though the setting of the book is in the 1930's, the novel has much to say about the fair treatment of all people, especially African-Americans.Lee addresses prejudice and tolerance and especially the courage it takes to make societal change. These ideas, combined with her personal experiences, probably influenced Lee to write her Pulitzer prize winning novel.