What does it take to make good people do bad things? Unlock the door to the criminal mind in The Line, the outstanding debut from Ireland's leading criminal psychologist.

Here Dr Ian Gargan unravels the motives of some of the nation's most violent and prodigious offenders, mapping the fine line between right and wrong - the set of life circumstances that could make any of us cross the line into criminality and violence, highlighting that there aren't many differences between us and them.

Based around real-life interviews he has conducted with criminals, which offer them an opportunity to confront and explain their actions while incarcerated, Gargan attempts to give a human voice to those incapable of speaking for themselves and to account for the tangled threads of circumstance and mental dysfunction that can propel once 'normal-living' people to the brink of horrifying acts ... and beyond.

Using insights garnered from interviewing and treating people, both within prison and out in the community, Gargan examines the spectrum of human behaviour that includes criminality, extreme beliefs and our own day-to-day intriguing thoughts.

The Line is a moving meditation on a life spent at the violent limits of human experience and a mirror held to the dark heart of human nature.