The Miracle of Forgiveness
The beginning of the book tells about all of us sinning and how even so-called minor sins have serious consequences. Elder Kimball discusses how to chart safe courses and counsels to avoid sin in many things. He also says negative things about those who don't forgive and positive things about those that do forgive.
The book is known for its bluntness in its treatment of sins such as homosexuality and adultery. However the book is also a message of hope and while emphasizing that it's better not to sin, it also declares that there is hope for the sinner.
Many people avoid reading much of it due to its harsh tones. In the LDS comedy, The RM, the main character, Jared, is given a copy of The Miracle of Forgiveness when arrested for driving a stolen car he didn't realize was stolen.
The Miracle of Forgiveness is sold in many languages and still in print to help sinners on the path to repentance.