One of the major themes in To Kill a Mockingbird is prejudice and race relations in the South. Tom Robinson's case, in which he is charged with raping a white woman, is reminiscent of the case of the Scottsboro Boys, nine young African-Americans from Alabama who were charged with raping two white women.
Find out more about the Scottsboro Boys , an excellent online exhibit of the Black History Museum.
To Kill a Mockingbird is set in the town of Maycomb, Alabama. Maycomb is fictional, but Alabama isn't. Learn more about the state of Alabama by visiting Alabama History On-Line from the Alabama Department of Archives and History.
To Kill a Mockingbird takes place during a period in United States (and world) history known as the Great Depression. A fine starting point to learning about this period of history on the WWW is the AITLC Guide to the Great Depression. There you'll find lots of links to further information.
Online information about the Great Depression is helopful, but often, a picture is worth many thousands of words. Online, you can find the works of four prominent photographers of the 1930s whose pictures document what life was like for so many Americans during the Great Depression, especially those in the South and the West.
See the pictures of --
Ben Shahn 
Arthur
Rothstein
Walker Evans
Dorothea Lange.
Also from the Library of Congress is this online exhibition of photographs of signs enforcing racial discrimination
The New Deal Network is also an excellent source for information and images from the 1930s. Be sure to look into the Image Library while you're there. You'll find a series of photographs taken in 1938 in Carbon Hill, Alabama.
Information about the novel's author, Harper Lee, can be found in this short article from The Christian Science Monitor. Biography.com also offers a short bio on Lee.
Check out this 1960 review of the novel, where it is described as "pleasant, undemanding reading."
Even more information about Harper Lee and her famous novel can be found on an extensively researched web page, Harper Lee & To Kill a Mockingbird.
Harper Lee grew up in Monroeville, Alabama. The town plays host to the Monroe County Heritage Museum. The museum is located in the town's courthouse which served as a model for the courthouse in the book as well as the film of To Kill a Mockingbird.
