By now we are all too familiar with the ghastly images that came out of Abu Ghraib prison in Iraq in 2004. But no one was more appalled than Philip Zimbardo, emeritus professor of psychology at Stanford University. They brought back to him chilling memories of the experiment he had conducted at Stanford thirty-three years earlier. To his horror, the behaviour of the guards seemed exactly to replicate what occurred in a basement of the university when he simulated conditions in a prison. Before long he was approached to act as an expert witness on behalf of one of the military policemen accused of abusing Iraqi prisoners. In The Lucifer Effect Zimbardo recounts the Stanford Prison Experiment and goes on to record his investigation of the real abuses that happened in Abu Ghraib. It is an absorbing work, packed with insight into human behaviour and streetwise observations that go back to his childhood in the South Bronx.

Zimbardo rejects the polarity of good versus evil and the common tendency to essentialise each to the exclusion of the other. Rather, he sees the potential for good and evil within everyone. He also rejects the notion that people are predisposed towards one or the other by virtue of genes,