There is a plethora of literature out there that has forgiveness as its main theme. Here are some of my favorite titles...
To Kill a Mockingbird: 50th Anniversary Edition
The Count of Monte Cristo (Everyman's Library)
Shadow Spinner (A Jean Karl Book)
A Tale of Two Cities
"First of all," he said, "if you can learn a simple trick, Scout, you'll get along a lot better with all kinds of folks. 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." To Kill a Mockingbird