The Roots of Evil is an accessible treatment of the problem of evil, suffering, and pain. Norman L. Geisler addresses the most pressing questions from a Christian perspective about why bad things happen to good people.
Norman L. Geisler (PhD, Loyola University of Chicago) taught at top evangelical colleges and seminaries for over fifty years and was a distinguished professor of apologetics and theology at Veritas Evangelical Seminary in Murrieta, California. He was the author of nearly eighty books, including the Baker Encyclopedia of Christian Apologetics and Christian Ethics. He and his wife lived in Charlotte, North Carolina.
This philosophical question has haunted me since my college days, when I actually took a course on it. It summarized many arguments about how the existence of evil, for many, proves that God doesn't exist, doesn't care, or some other conclusion.
For me, I have decided that this topic is a temptation towards atheism, and have in the end decided to abandon it. Evil, at least the best definition I have come across, is a lack of good, a lack in the something that God created, and was not created by God Himself. This Augustinian definition seems to be the best fit that I can come up with.
It fits well with the Silmarillion story of creation by Tolkien, explains, for me, a lot of the philosophy about the existence of evil, and solves the issue. Evil will be conquered by an all good, all loving God, in time.