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Why Did They Do It?
The cases that stunned Australia - and left us all with one question: why did they do it?
Gerard Baden-Clay was described as charming and successful, with a picture-perfect life, until he murdered his wife, Allison. John Myles Sharpe killed his pregnant wife and their young daughter with a spear gun. Simon Gittany flung his fiancée off the balcony of his upmarket inner-city apartment, having proposed lovingly to her, in public, just two months before. These and other crimes, committed by people described as average, ordinary, normal...
In Why Did They Do It?, respected journalist Cheryl Critchley teams with esteemed psychologist Dr Helen McGrath to dissect the cases and identify the personality disorders of each of the killers. Using psychological analysis, combined with scientific evidence, they identify the reasoning and motives of the men and women whose brutal crimes shocked the nation.
AUTHOR INFORMATION
Professor Helen McGrath has worked for many years as a psychologist in both a hospital setting and in private practice. She is currently an adjunct professor at both Deakin University and RMIT University. She is the author/co-author of twenty-two books for psychologists, other professionals and the general community, including Bounce Back!, Difficult Personalities and Friends.
Cheryl Critchley is a respected Melbourne investigative journalist with thirty years' experience on a range of publications. She is the author of six books on topics as diverse as AFL football, parenting and Melbourne Zoo's first baby elephant. She now writes and edits for the Weekly Review and several other publications.
Gerard Baden-Clay was described as charming and successful, with a picture-perfect life, until he murdered his wife, Allison. John Myles Sharpe killed his pregnant wife and their young daughter with a spear gun. Simon Gittany flung his fiancée off the balcony of his upmarket inner-city apartment, having proposed lovingly to her, in public, just two months before. These and other crimes, committed by people described as average, ordinary, normal...
In Why Did They Do It?, respected journalist Cheryl Critchley teams with esteemed psychologist Dr Helen McGrath to dissect the cases and identify the personality disorders of each of the killers. Using psychological analysis, combined with scientific evidence, they identify the reasoning and motives of the men and women whose brutal crimes shocked the nation.
AUTHOR INFORMATION
Professor Helen McGrath has worked for many years as a psychologist in both a hospital setting and in private practice. She is currently an adjunct professor at both Deakin University and RMIT University. She is the author/co-author of twenty-two books for psychologists, other professionals and the general community, including Bounce Back!, Difficult Personalities and Friends.
Cheryl Critchley is a respected Melbourne investigative journalist with thirty years' experience on a range of publications. She is the author of six books on topics as diverse as AFL football, parenting and Melbourne Zoo's first baby elephant. She now writes and edits for the Weekly Review and several other publications.
400 pages, Paperback
First published January 1, 2015
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Displaying 1 - 18 of 18 reviews
June 11, 2016
This book was very interesting. It examines 'why' certain shocking crimes in Australia took place in the context of the perpetrators having personality disorders. I had always assumed that personality disorders were mental illnesses so I realised pretty quickly that I had a lot to learn. When it was stated how common personality disorders are, I was concerned that people who haven't harmed anyone could be unfairly prejudiced by being compared to killers, however I think that people reading this book are intelligent enough not to do that and the writers make it very clear that a personality disorder is not a prerequisite to murder. People still have 100% control over their actions and decisions.
Having completed a law degree, the 'why' question was never asked. Cases were always assessed very clinically in matters of law and anything to do with the offender's personality was only looked at in terms if the legal definition of insanity, which barely any offender meets. I never had to delve much further, although like anyone who watches the news and hears about the awful things that people do to each other I wanted to know why they did it, how they could be so cruel and why did they think they'd get away with it?
This book helps answer some of these questions by understanding the offender's personality. It definitely answers the 'how can a sane person do that?' question.
It actually made me angrier and more upset when I started to understand because it all seems so pointless. None of the victims had to die and none of them died for a remotely justifiable reason. Anyone who killed to cover up something did such a poor job of it that they need not have killed in the first place. I needed to put the book down and walk away at times because the cases which we've seen all over the news are still very upsetting. I don't have the clinical view of law that I did when I was studying anymore. I knew pretty quickly that I didn't fit into that narcissistic world because I felt too much. Now I'm glad that I feel things because if I didn't I would be like some of the people in this book.
Having completed a law degree, the 'why' question was never asked. Cases were always assessed very clinically in matters of law and anything to do with the offender's personality was only looked at in terms if the legal definition of insanity, which barely any offender meets. I never had to delve much further, although like anyone who watches the news and hears about the awful things that people do to each other I wanted to know why they did it, how they could be so cruel and why did they think they'd get away with it?
This book helps answer some of these questions by understanding the offender's personality. It definitely answers the 'how can a sane person do that?' question.
It actually made me angrier and more upset when I started to understand because it all seems so pointless. None of the victims had to die and none of them died for a remotely justifiable reason. Anyone who killed to cover up something did such a poor job of it that they need not have killed in the first place. I needed to put the book down and walk away at times because the cases which we've seen all over the news are still very upsetting. I don't have the clinical view of law that I did when I was studying anymore. I knew pretty quickly that I didn't fit into that narcissistic world because I felt too much. Now I'm glad that I feel things because if I didn't I would be like some of the people in this book.
May 22, 2019
3.5 stars
December 9, 2016
A different take on true crime stories: a psychologist teams up with a reporter to look at the reasons behind some of the crimes Australians find incomprehensible. It includes a guy who drove his kids into a dam, a woman who cooked her partner, the guy who burned down a nursing home to cover up his theft of painkillers. They look at the facts of the case, and the known history of the criminal's life, to explain how someone reached a point where they thought those were reasonable things to do.
The cases are grouped by personality disorder based on assessments made at the time of sentencing, so there's no diagnosis-at-a-distance, which is good. Careful explanations are given of the difference between mental illness (schizophrenia, depression, etc), legal capacity (understanding right/wrong and consequences) and personality disorders (anti-social, narcissistic, etc). Heaps of references are given to other writing on the case, either in books or in the news, plus a nice long bibliography at the end if there's anything you want more details on. And each section ends with a "what can we learn from this" summary, with useful contacts in case you know someone showing similar traits.
I much prefer this approach to just lumping everything under "crazy" as in "well, you'd have to be crazy to do something like that". If we want to prevent these sorts of crimes from happening again, we have to understand how they happen instead of just brushing it off with a cliche. That means taking a long, hard look at medical, psychological and social factors and seeing if there's anything we can do before things get out of hand.
The cases are grouped by personality disorder based on assessments made at the time of sentencing, so there's no diagnosis-at-a-distance, which is good. Careful explanations are given of the difference between mental illness (schizophrenia, depression, etc), legal capacity (understanding right/wrong and consequences) and personality disorders (anti-social, narcissistic, etc). Heaps of references are given to other writing on the case, either in books or in the news, plus a nice long bibliography at the end if there's anything you want more details on. And each section ends with a "what can we learn from this" summary, with useful contacts in case you know someone showing similar traits.
I much prefer this approach to just lumping everything under "crazy" as in "well, you'd have to be crazy to do something like that". If we want to prevent these sorts of crimes from happening again, we have to understand how they happen instead of just brushing it off with a cliche. That means taking a long, hard look at medical, psychological and social factors and seeing if there's anything we can do before things get out of hand.
January 14, 2017
Really interesting book and written in plain English. I recommend it for anyone interested in criminal psychology.
March 4, 2019
Incredibly chilling book, covering all the grizzly details as to why the most unlikely people commit the most heinous of crimes.
Covering a multitude of personality disorders, this book attempts to pry into the minds of some of Australia's deadliest killers.
The Avoidants:
Robert Farquharson. Drowned his three young sons when he plunged his vehicle into a dam near their rural Victorian home. He still denies murdering his own flesh and blood in an attempt to pay back his wife for leaving him.
John Myles Sharpe. Brutally murdered his pregnant wife and toddler by shooting a spear gun straight through their skulls. He didn't want the second child his wife was carrying.
The Narcissists:
Peter Caruso. Bludgeoned his wife of almost 50 years to death with a hatchet after discovering she was planning on leaving him.
Gerard Baden-Clay. He killed his wife and mother of his children when she found out he was continuing his infidelity after he promised he would stop.
Roger Dean. Set fire to a Quakers Hill nursing home after stealing almost 300 tablets of prescription painkillers. 14 residents of the home succumbed to the flames.
Keli Lane. Left her two day old daughter to die in the woods when she didn't fit in with Keli's plans to become an Olympic water polo player and continue to party and seduce multitudes of men.
The Borderline:
Katherine Knight. Murdered, skinned, and cooked her partner Pricey when she thought he was going to leave her. She was the first woman in Australia to be handed a sentence of life without parole in 2000.
The Antisocials:
Simon Gittany. Threw his fiancee off his 15th storey balcony when he discovered she was leaving him, after discovering that he was monitoring her emails and texts, and controlling her every move.
Angelika Gavare. Murdered an elderly pensioner for financial gain.
Adrian Bayley. Killed Jill Meagher after brutally raping her because she threatened to expose him.
All of these names are embedded in the dark underbelly of Australia's murder history. But why did they commit these horrendous crimes? And why do many of them still deny any wrongdoing, with several having already appealed their sentences at the publication of this book.
The answers are still eluding me, unable to comprehend why it could ever get to the point where you feel you must murder someone, especially someone you love, or someone vulnerable.
But this book does shed light on the motivations of these cold-blooded killers, even if we may never truly understand them.
Covering a multitude of personality disorders, this book attempts to pry into the minds of some of Australia's deadliest killers.
The Avoidants:
Robert Farquharson. Drowned his three young sons when he plunged his vehicle into a dam near their rural Victorian home. He still denies murdering his own flesh and blood in an attempt to pay back his wife for leaving him.
John Myles Sharpe. Brutally murdered his pregnant wife and toddler by shooting a spear gun straight through their skulls. He didn't want the second child his wife was carrying.
The Narcissists:
Peter Caruso. Bludgeoned his wife of almost 50 years to death with a hatchet after discovering she was planning on leaving him.
Gerard Baden-Clay. He killed his wife and mother of his children when she found out he was continuing his infidelity after he promised he would stop.
Roger Dean. Set fire to a Quakers Hill nursing home after stealing almost 300 tablets of prescription painkillers. 14 residents of the home succumbed to the flames.
Keli Lane. Left her two day old daughter to die in the woods when she didn't fit in with Keli's plans to become an Olympic water polo player and continue to party and seduce multitudes of men.
The Borderline:
Katherine Knight. Murdered, skinned, and cooked her partner Pricey when she thought he was going to leave her. She was the first woman in Australia to be handed a sentence of life without parole in 2000.
The Antisocials:
Simon Gittany. Threw his fiancee off his 15th storey balcony when he discovered she was leaving him, after discovering that he was monitoring her emails and texts, and controlling her every move.
Angelika Gavare. Murdered an elderly pensioner for financial gain.
Adrian Bayley. Killed Jill Meagher after brutally raping her because she threatened to expose him.
All of these names are embedded in the dark underbelly of Australia's murder history. But why did they commit these horrendous crimes? And why do many of them still deny any wrongdoing, with several having already appealed their sentences at the publication of this book.
The answers are still eluding me, unable to comprehend why it could ever get to the point where you feel you must murder someone, especially someone you love, or someone vulnerable.
But this book does shed light on the motivations of these cold-blooded killers, even if we may never truly understand them.
March 4, 2025
This book takes a deep dive into the psychology behind some of Australia’s most shocking crimes, exploring what drives people to commit unthinkable acts. Rather than just recounting the cases, Why Did They Do It? examines the motives, personalities, and psychological factors at play, giving readers a broader understanding of criminal behavior.
I found it particularly interesting how Cheryl Critchley and Dr. Helen McGrath break down different types of offenders and their reasoning, making complex psychological concepts accessible. The mix of true crime storytelling with expert analysis provides a fresh perspective on why certain people cross the line into criminality.
A fascinating and thought-provoking read for anyone interested in forensic psychology, criminal profiling, or the deeper motivations behind crime. Highly recommended for those who want to go beyond the headlines and understand the “why” behind the “what.”
I found it particularly interesting how Cheryl Critchley and Dr. Helen McGrath break down different types of offenders and their reasoning, making complex psychological concepts accessible. The mix of true crime storytelling with expert analysis provides a fresh perspective on why certain people cross the line into criminality.
A fascinating and thought-provoking read for anyone interested in forensic psychology, criminal profiling, or the deeper motivations behind crime. Highly recommended for those who want to go beyond the headlines and understand the “why” behind the “what.”
September 14, 2025
This book takes a deep dive into the psychology behind some of Australia’s most shocking crimes, exploring what drives people to commit unthinkable acts. Rather than just recounting the cases, Why Did They Do It? examines the motives, personalities, and psychological factors at play, giving readers a broader understanding of criminal behavior.
I found it particularly interesting how Cheryl Critchley and Dr. Helen McGrath break down different types of offenders and their reasoning, making complex psychological concepts accessible. The mix of true crime storytelling with expert analysis provides a fresh perspective on why certain people cross the line into criminality.
A fascinating and thought-provoking read for anyone interested in forensic psychology, criminal profiling, or the deeper motivations behind crime. Highly recommended for those who want to go beyond the headlines and understand the “why” behind the “what.”
I found it particularly interesting how Cheryl Critchley and Dr. Helen McGrath break down different types of offenders and their reasoning, making complex psychological concepts accessible. The mix of true crime storytelling with expert analysis provides a fresh perspective on why certain people cross the line into criminality.
A fascinating and thought-provoking read for anyone interested in forensic psychology, criminal profiling, or the deeper motivations behind crime. Highly recommended for those who want to go beyond the headlines and understand the “why” behind the “what.”
February 7, 2017
This was a very gripping account of some of the worst crimes in Australia's history and the personalities behind them. By looking at 10 murderers in terms of the probability they had a serious personality disorder the authors provide an insight into how someone could commit such awful crimes and why they're not legally insane for doing so.
It was often pretty harrowing reading about these crimes, but in the end the justice system finally came through and the families involved are able to move on to the best of their ability.
It was often pretty harrowing reading about these crimes, but in the end the justice system finally came through and the families involved are able to move on to the best of their ability.
January 9, 2021
Very insightful, though I disagreed with some of the perspectives I thoroughly enjoyed this book as a whole.
November 13, 2023
incredible incredible incredible. love how it makes you think about the factors that went into the rationalising of murder
July 21, 2024
Enjoyed the content of the book but I didn't like how it was written
January 20, 2025
As someone with BPD, I read this because I wanted to understand more about myself. It was intriguing and I did really enjoy it.
December 13, 2015
An interesting take on crimes committed by some of the worst criminals of recent years.
In the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association, as well as the standard diagnoses of definite mental illnesses – depression; bipolar disorder; schizophrenia – there is a category labelled "personality disorders". Four of these are used to classify ten criminals, from Robert Farquharson, who drove a car into a dam near Winchelsea, killing his three sons, to Adrian Bayley, the vicious killer of journalist Jill Meaghar. Farquharson is presented as an example of "Avoidant Personality Disorder": anxious, socially inept, shunning responsibility and totally lacking in confidence; the sort of person who gives control of his life over to a stronger personality, but bitterly resents this control. Farquharson killed their three sons when his wife left him for another man. He tried to disguise this as an accident, probably hoping this would garner him sympathy, but failed to get away with it.
Bayley, on the other hand, is an example of "Antisocial Personality Disorder": predatory, deceitful, lacking in conscience or remorse for the harm they cause others, sometimes called sociopaths. Lying and cheating come easily to them and, as in Bayley's case, acting with brutality on impulse. Bayley killed Meagher for resisting his attack and attempting to get away.
Only one case is cited under "Borderline Personality Disorder" – famously, the condition identified with Marilyn Monroe in Anthony Summers' book Goddess. The case of Katherine Knight is far removed from Monroe, however. Knight stabbed her partner, John Price, at least 37 times and let him bleed to death, as punishment for his decision to leave her. Borderlines are usually the products of violent, chaotic backgrounds and grow up to have extremely unstable, often violent personalities themselves. Knight's violence and frequent threats to kill him had already put Price in fear of his life. She tried to make the murder look like an episode of temporary insanity, but the court didn't buy it and she was sentenced to life imprisonment without parole – the first Australian woman to receive this sentence, which was upheld despite her appeal.
It is almost laughably predictable that “Narcissistic Personality Disorder" contains the most entries, four in all. The best-known is Gerard Baden-Clay, whose 2012 conviction for the murder of his wife Allison has just been set aside. Baden-Clay reputedly thought the world of himself but was in financial and amatory dire straits at the time he killed his wife – either accidentally or deliberately. Another famous case is that of Keli Lane, whose daughter, Tegan, disappeared shortly after Lane gave birth to her. Lane, an elite water polo player, did not want pregnancies to interfere with her sporting career. Despite Tegan’s body or whereabouts never having been discovered, Lane was sentenced to 18 years for murder.
One case that could have been added is that of Derek Percy – the child-killer who became a prime suspect in the disappearance of the Beaumont children from an Adelaide beach in 1966. In Debi Marshall’s Lambs to the Slaughter, Percy is identified as possibly an exponent of “Schizoid Personality Disorder”. Schizoids have an enigmatic persona, keeping to themselves a great deal and being easily forgotten. They compensate for social inadequacy by virtually inhabiting a fantasy life. However, this diagnosis does not account for Percy’s brutality and the same applies to most of the other cases. What tips a person over the edge into violence and depravity? Does anyone really have the answer? Sometimes I think novelists get further with their explanations than true-crime writers!
In the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association, as well as the standard diagnoses of definite mental illnesses – depression; bipolar disorder; schizophrenia – there is a category labelled "personality disorders". Four of these are used to classify ten criminals, from Robert Farquharson, who drove a car into a dam near Winchelsea, killing his three sons, to Adrian Bayley, the vicious killer of journalist Jill Meaghar. Farquharson is presented as an example of "Avoidant Personality Disorder": anxious, socially inept, shunning responsibility and totally lacking in confidence; the sort of person who gives control of his life over to a stronger personality, but bitterly resents this control. Farquharson killed their three sons when his wife left him for another man. He tried to disguise this as an accident, probably hoping this would garner him sympathy, but failed to get away with it.
Bayley, on the other hand, is an example of "Antisocial Personality Disorder": predatory, deceitful, lacking in conscience or remorse for the harm they cause others, sometimes called sociopaths. Lying and cheating come easily to them and, as in Bayley's case, acting with brutality on impulse. Bayley killed Meagher for resisting his attack and attempting to get away.
Only one case is cited under "Borderline Personality Disorder" – famously, the condition identified with Marilyn Monroe in Anthony Summers' book Goddess. The case of Katherine Knight is far removed from Monroe, however. Knight stabbed her partner, John Price, at least 37 times and let him bleed to death, as punishment for his decision to leave her. Borderlines are usually the products of violent, chaotic backgrounds and grow up to have extremely unstable, often violent personalities themselves. Knight's violence and frequent threats to kill him had already put Price in fear of his life. She tried to make the murder look like an episode of temporary insanity, but the court didn't buy it and she was sentenced to life imprisonment without parole – the first Australian woman to receive this sentence, which was upheld despite her appeal.
It is almost laughably predictable that “Narcissistic Personality Disorder" contains the most entries, four in all. The best-known is Gerard Baden-Clay, whose 2012 conviction for the murder of his wife Allison has just been set aside. Baden-Clay reputedly thought the world of himself but was in financial and amatory dire straits at the time he killed his wife – either accidentally or deliberately. Another famous case is that of Keli Lane, whose daughter, Tegan, disappeared shortly after Lane gave birth to her. Lane, an elite water polo player, did not want pregnancies to interfere with her sporting career. Despite Tegan’s body or whereabouts never having been discovered, Lane was sentenced to 18 years for murder.
One case that could have been added is that of Derek Percy – the child-killer who became a prime suspect in the disappearance of the Beaumont children from an Adelaide beach in 1966. In Debi Marshall’s Lambs to the Slaughter, Percy is identified as possibly an exponent of “Schizoid Personality Disorder”. Schizoids have an enigmatic persona, keeping to themselves a great deal and being easily forgotten. They compensate for social inadequacy by virtually inhabiting a fantasy life. However, this diagnosis does not account for Percy’s brutality and the same applies to most of the other cases. What tips a person over the edge into violence and depravity? Does anyone really have the answer? Sometimes I think novelists get further with their explanations than true-crime writers!
August 8, 2015
Very interesting reading, gruesome in parts & even with the psychological analysis it is difficult to comprehend the evil within these people.
January 19, 2016
3.5 stars.
August 18, 2016
This was a great book, very interesting.
Killer can be anywhere in society amongst us all.
From different backgrounds, kill for different reasons.
Killer can be anywhere in society amongst us all.
From different backgrounds, kill for different reasons.
December 22, 2016
I think I should've been a forensic psychologist. True crime books always fascinate me.
March 28, 2017
Between the Covers Reviews:
I have a problem with buying books. I can’t seem to resist the smell of a new book’s freshly-printed pages or the rough edges of a well-loved one. I’m sure I’m not alone in this. I was supposed to be browsing, during a work break, when I came across ‘Why Did They Do It?’ I’m a sucker for an interesting cover and the graphics and title pulled at my curiosity. As soon as I began reading the blurb I was hooked. Why did these everyday Australians become callous killers that shocked the nation?
3 sentence summary
Why Did They Do It? explains that many criminals, especially those that commit crimes seemingly out of the blue, suffer from personality disorders, rather than being ‘evil’ or suffering from a mental illness. A personality disorder occurs when an individual’s permanent pattern of thinking and feeling becomes 1) inflexible and maladaptive 2) causes personal distress to oneself and to others and 3) are pervasive across a broad range of personal and social situations. People with these personality disorders often lack resilience under stress, are stubborn and do not adapt to changing circumstances which often puts them at odds with the people in their lives and can end up causing long term harm, and in the worst case scenario, death.
Want to read the full review?
Check out my book blog Between the Covers
I have a problem with buying books. I can’t seem to resist the smell of a new book’s freshly-printed pages or the rough edges of a well-loved one. I’m sure I’m not alone in this. I was supposed to be browsing, during a work break, when I came across ‘Why Did They Do It?’ I’m a sucker for an interesting cover and the graphics and title pulled at my curiosity. As soon as I began reading the blurb I was hooked. Why did these everyday Australians become callous killers that shocked the nation?
3 sentence summary
Why Did They Do It? explains that many criminals, especially those that commit crimes seemingly out of the blue, suffer from personality disorders, rather than being ‘evil’ or suffering from a mental illness. A personality disorder occurs when an individual’s permanent pattern of thinking and feeling becomes 1) inflexible and maladaptive 2) causes personal distress to oneself and to others and 3) are pervasive across a broad range of personal and social situations. People with these personality disorders often lack resilience under stress, are stubborn and do not adapt to changing circumstances which often puts them at odds with the people in their lives and can end up causing long term harm, and in the worst case scenario, death.
Want to read the full review?
Check out my book blog Between the Covers
Displaying 1 - 18 of 18 reviews