It's just as well Kent Kiehl doesn't get to take his work home.
His fascination is criminal psychopaths, a capricious combination of crime and flawed thinking that produces at its worst a living nightmare -- a cunning, scary, dangerous crook who seemingly can't be human, yet seems persuasively so.
In The Psychopath Whisperer, brain scientist Kiehl writes with colour and skill about these people behind bars.
Many of his subjects are career criminals in maximum-security detention for a variety of serious, often violent crimes, including multiple murders, rapes, assaults and/or robberies.
As the men at the top of the psychopathic food chain, they're outwardly civilized, but in reality are as destructive or lethal as a smiling Rottweiler or Anthony Hopkins' Hannibal the cannibal in The Silence of the Lambs.
Not every crook is a psychopath, and not every psychopath a crook. But put them together in the same head and you've got a truly frightening instrument that doesn't behave; psychopaths commit one of every four murders in the U.S.
Although estimates vary, 15 to 25 per cent of the prison population is psychopathic, as is about one per cent of adult males in the outside population.
A young, leading investigator of psychopathy, Kiehl indicates that while progress is being made, it would likely be easier to tame an African lion with a wooden spoon than figure out what's cooking in the heads of North America's worst psychopaths -- and whether science can one day free them of their self-destructive ways.
An important question Kiehl doesn't explore is whether the public supports the reintegration of any of the mentally ill (let alone criminal psychopaths) who have committed egregious acts but are deemed fit thanks to drugs and/or therapy.
Kiehl's book is interesting, even ghoulishly entertaining; at times it reads like a thinking man's horror story, or a dose of Stephen King in real life as he recounts his experiences with chilling people inside both Canadian and U.S. prisons.
The worst of the psychopaths are inside prison (or should be); they are rational and know right from wrong but just can't care. They're egocentric, have zero empathy, no conscience, no moral compass, can't love, can smooth-talk better than a televangelist and can con better than a carnival barker.
To call the men Kiehl studies simply anti-social is like saying Canadian murderers Robert Pickton, Paul Bernardo and the late Clifford Olsen just don't get along with people.
Kiehl concludes criminal psychopaths' minds are flawed. Using MRI technology for the first time in prisons, he scanned the brains of over 500 psychopaths as well as 3,000 violent offenders. His groundbreaking brain-imagery studies have advanced research in the field by leaps and bounds, because the images prove what he believes.
These moving images show the brain at work, and Kiehl is able to see that psychopaths' minds function differently than ours: their brains are impaired in a number of regions, they find it hard to process abstracts, and their minds react to sounds in the same way as people with certain brain damage.
Long before Kiehl, the late famous psychiatrist Dr. Karl Menninger spoke of society's zealous pursuit of revenge and its unwillingness to forgive in his landmark 1968 book, The Crime of Punishment.
Perhaps Kiehl's work will one day help us get to the point where there will be no crime of punishment -- at least for criminal psychopaths -- because science will have found the remedy for their flawed brains. Or is that too much serendipity to expect?
Whatever happens, we'd still be left with the vengeful, ruthless, narcissistic, troublesome psychopaths living among us who are not criminals.
And then there are the "successful" psychopaths, whose character traits help them do well in politics, business and entertainment because they're determined at all costs to get what they want.
Some investigators speculate these three career categories are full of such people, but they really don't know.
Unfortunately, Kiehl leaves up to us how we cope with all of this.
Barry Craig is a retired journalist.