The Lucifer Effect: Understanding How Good People Turn Evil is a 2007 book which includes professor Philip Zimbardo's first detailed, written account of the events surrounding the 1971 Stanford Prison Experiment (SPE) — a prison simulation study which had to be discontinued after only six days due to several distressing outcomes and mental breaks of the participants. The book includes over 30 years of subsequent research into the psychological and social factors which result in immoral acts being committed by otherwise moral people. It also examines the prisoner abuse at Abu Ghraib in 2003, which has similarities to the Stanford experiment. The title takes its name from the pious story of the favored angel of God, Lucifer, his fall from grace, and his assumption of the role of Satan, the embodiment of evil. The book was briefly on "The New York Times" Non-Fiction Best Seller and won the American Psychological Association's 2008 William James Book Award.