There is a continuum of psychopathy measured by a diagnostic checklist of behaviour know as Hare's Psychopathy Checklist. The scale ranges from 0 to 40 and anyone who measures 25 or over is classified as a psychopath. An astonishing 3% of the general population fall into this category.
The psycho in your life could be your boss, your teenage child, your blind date, the person who sits opposite you at work, your relation, your doctor or your lover. They could wear a smart suit or a tracksuit, they could be male or female, they might be a high-flying big earner or a mother of five living on benefits. What they will share is a cluster of emotional abnormalities and antisocial behaviours: they may be manipulative, have a superficial charm, show a lack of remorse or guilt, they will no doubt have a total lack of empathy, have an inability to feel revulsion, they'll take risks and have a lack of emotional range.
The Devil You Know will expain the psychology of psychopaths. It shows how these forms of behaviour - fairly harmless when found alone - can cluster together to form a potentially dangerous mix. As a society we are culturally led to believe that things are our own fault but this book shatters that myth in a very empowering, informative and entertaining way.