In our society of bitter caricature, evil actions are only perpetrated by evil people—Saddam Hussein, death row murderers, and George W. Bush, to name a few common targets. Pointing fingers seems like the easiest course of action whenever a problem arises. “I could never do what they do,” we tell ourselves. But as famed psychologist Philip Zimbardo reminds us, we are all capable of distasteful, even evil, actions, given the right situation.

As anyone who has taken an introductory psychology course knows, Zimbardo was the creator and lead experimenter in the infamous Stanford Prison Experiment (SPE) of 1971, which resulted in the “dominant conclusion…that the pervasive yet subtle power of a host of situational variables can dominate an individual’s will to resist.”

The study involved Stanford undergraduate and graduate students role-playing the parts of prisoners and prison guards. Zimbardo originally envisioned a two-week study in which he could closely observe the behavioral changes of otherwise normal people when incarcerated. “If you put good people in a bad place, do the people triumph or does the place corrupt them?” he recalls asking himself. In the important and captivating “The Lucifer Effect,” Zimbardo attempts to answer this question and explore its many disturbing implications.

Any attentive psychology student can tell you what happened with the experiment: The situation got ugly very quickly. During the Thursday night-shift after the initial Sunday faux-arrests, the prison guards began forcing the male prisoners to engage in simulated sodomy.

“Now you two, you’re male camels. Stand behind the female camels and hump them,” ordered one of the guards, in Zimbardo’s recount of the events. He and his team were forced to terminate the experiment early due to the increasing levels of extreme sexual and mental humiliation the prisoners were experiencing.

To this day, Zimbardo admits that he is still distraught about the events that occurred and feels guilty because he did not end the experiment even earlier.

Zimbardo’s regret is evident from the opening of his preface. “I wish I could say that writing this book was a labor of love; it was not that for a single moment of the two years it took to complete,” he writes. “It was emotionally painful to review all of the videotapes from the Stanford Prison Experiment.”

Indeed, many fellow psychologists have criticized this monumental experiment on multiple grounds. Some believed that too many external factors influenced the process, rendering the results inaccurate and unscientific. Others berated Zimbardo for the unethical nature of the experiment, itself. Many current procedures and protocols for psychological testing resulted from the scrutiny of the incident.

Yet, despite these existing responses, I have no doubt that this book had to be written. If the first part of the book was simply a detailed treatment of one of the most important studies of human nature, then the second half is the crucial dissection and evaluation.

Unsurprisingly, Zimbardo draws parallels between the SPE and the recent Abu Ghraib torture and abuse scandal. His interpretations of the actions of the soldiers through the lens of his experience are enlightening: Though initially disgusted by the soldiers’ actions, Zimbardo eventually testified on their behalf in military court martial proceedings, arguing that any person, if pressured under a certain set of conditions and circumstances, could easily sink to the level of those whose actions we find revolting. If it were not for the intriguing subject matter and the eerie conclusions drawn, “The Lucifer Effect” could be a difficult read indeed. Difficult, in this case, does not mean that his writing is dense and complex. Rather, Zimbardo’s prose is sometimes hard to read simply because it isn’t very eloquent. He writes like a scientist: past events come across as if they were entries in a study or report. Like observational entries in a report, sentences are often choppy and transitions seemed somewhat unnatural.

But while the text is problematic on the micro-level, on the macro-level, Zimbardo proves to be a masterful narrator and paces the story at just the right speed. He is also a lucky man: the material and subject matter naturally invites the curiosity of the reader and allows him to overlook Zimbardo’s occasionally poorly worded phrase or tendency to dwell on a tangentially related subject.

In the end, these defects feel less like defects and more like the idiosyncratic quirks of a charming explorer who desperately wants us to understand a new and terrifying world that he’s discovered.

—Reviewer Eric W. Lin can be reached at ericlin@fas.harvard.edu.