What is the central message that Harper Lee is conveying to the reader in To Kill a Mockingbird?

Harper Lee's central message in To Kill a
Mockingbird evolves around the primary themes of prejudice, intolerance and
innocence. Atticus' advice to Scout in Chapter 3 best sums up the author's
intent:

"You
never really understand a person until you consider things from his point of view--until
you climb into his skin and walk around in
it."

It is a message about
the importance of tolerance: how an individual's actions and beliefs may differ from
your own, and how they should be considered and respected before formulating an opinion.
The message of tolerance goes hand in hand with that of prejudice, and how many
characters are prematurely judged by the color of their skin (Tom Robinson), from gossip
and rumor (Boo Radley), and from their eccentric nature (Dolphus Raymond). The theme of
innocence is also explored in the novel, both from the aspect of the falsely accused
(Tom, Boo) and the loss of innocence experienced by Jem, Scout and
Dill.