This was not a very good book. Having listened to several audiobooks about psychopaths, notably Martha Stout's The Sociopath Next Door and Jon Ronson's The Psychopath Test, I think the lesson learned here is that journalists are better writers than academics.
Criminal psychologist Robert Hare is famous for having devised the Hare Psychopathy Checklist, which is referenced several times by Stout and Ronson. However, in this book he spends entirely too much time talking about how much research he's done and how clever he is to have formulated this unique way of studying and understanding psychopaths, yet the actual evidence he cites is largely anecdotal and even speculative at times. I started to doubt the doc's credibility about the third time he used fictional characters (e.g., Hannibal Lecter, Buffalo Bill) to make a point.
He does this throughout Without Conscience: he will describe psychopathic behavior, and then use a sensationalist example, often from a movie! He talks about psychopaths as if they are monsters who are practically a separate species. Granted, many psychopaths, even those who aren't murderers, are monsters. But it hardly seems useful or truly serving the cause of truthful inquiry to dwell on how horrible psychopaths are, using serial killers as the primary examples, even though Hare himself admits that serial killers are an extreme minority of psychopaths, rather than addressing more interesting and informative questions like how to identify psychopaths and what to do about them.
Martha Stout and Jon Ronson cover much the same ground, and while of course they talk about the most spectacular, cruel, and flamboyant psychopaths as well — serial killers, bigamists, con-men, etc. — they do both more entertainingly and with a little more sense of balance, addressing the fact that most psychopaths, while horrible people to deal with, live fairly ordinary lives (often miserable ones), doing as much damage to themselves as others. Whereas Hare seems to want everyone to hire a professional like himself and apply the Hare Psychopathy Checklist whenever you suspect you're dealing with a psychopath, which could be anyone who exhibits any psychopathic behaviors.
Here is where Hare's book also seems to flounder: he uses many examples of psychopathic behavior, and conflates them with psychopaths. Rapists, for example, are "often" psychopaths, he says. Yet while noting that not all rapists are psychopaths and not all psychopaths are rapists, Hare then goes on to describe rape as a crime that is typical of a psychopathic mindset, the extreme lack of empathy for others, the lack of impulse control, etc. Okay, and? What does this actually tell us about the relationship between rape and psychopathy?
He makes vague assertions about how various crimes, from stock market manipulation to government fraud and abuse to violent crime, "may" be the result of psychopaths, and that this is evident of the massive social and economic damage psychopaths do. Well, yes, I'm sure a lot of Wall Street predators and street-level grifters and conniving, bad people everywhere in-between are psychopaths, but not all of them, so just how many are and what is the measurable contribution of psychopaths to our social ills? It's impossible to say, but Hare just hints that psychopaths are becoming more common, as evidenced by how much "worse" society is getting - again, with no evidence.
The few chapters that were interesting and informative were those that talked about what makes a psychopath's brain different — they seem to often have linguistic mannerisms like misusing words or inventing neologisms, and they also seem to often have poor impulse control, an inability to control themselves even when they may be very smart and quite capable of foreseeing the consequences of their actions. This would also explain why psychopaths tend to get caught out eventually, whether they are serial killers or just that lying manipulator in your office who's always telling stories behind people's back.
Hare does not offer much hope for the treatment of psychopaths, since he points out the condition seems to start in childhood, if not at birth, and no form of behavioral therapy actually changes them: at best, you might convince a psychopath to "play by the rules" so long as they are convinced it's in their best interests.
Overall, while there were some interesting bits and a very comprehensive description of psychopathy, Without Conscience appeared to me to be scientifically weak, too much a vehicle for Robert Hare to promote himself and his work, and not as good as other books that have covered the same subject.