I summarize more than 30 years of research on factors that can create a "perfect storm" which leads good people to engage in evil actions. This transformation of human character is what I call the "Lucifer Effect," named after God's favorite angel, Lucifer, who fell from grace and ultimately became Satan.
Rather than providing a religious analysis, however, I offer a psychological account of how ordinary people sometimes turn evil and commit unspeakable acts.

In his introduction to his site on The Lucifer Effect (2007)