Aileen's partner 

Film

Aileen's partner is Selby Wall, a young woman from Ohio who, after a row with her parents regarding her lesbianism, is staying in Florida with friends of her family.  A broken arm and the resulting inability to find work mean that Selby is facing a return to her parents.  When Aileen invites Selby to get together with her, Selby sees this as an escape. 

Reality

During the period of her life depicted in Monster, Aileen Wuornos's partner was Tyria Moore.  Moore was from Ohio and moved to Florida, independently, two years before meeting Wuornos.  Tyria Moore was understood to have good relationships with her father, stepmother and many siblings  
 

Comment

Legal issues must have prevented the makers of Monster from using Tyria Moore's name but, due to other differences, Selby must be regarded as a fictional substitute for Tyria, as opposed to a “name changed for legal reasons” representation of her.  Also, Charlize Theron's Aileen, with her rough complexion and stringy hair, is a near double of the real Aileen Wuornos.  With this in mind, it seems odd that the film's other main character, Christina Ricci's Selby, looks nothing like her real life counterpart (Tyria Moore was a plump woman with missing teeth).  This is probably due to commercial considerations: by giving the film one good looking main character, the makers of Monster were able to boost the film's box office potential. 
 
Timeline (1) 

Film

Aileen and Selby meet just two days before Aileen kills for the first time.  Although the ages of the characters are not specified, their appearances suggest that Aileen is in her mid thirties whilst Selby is in her late teens.

Reality
Aileen Wuornos and Tyria Moore first met in July 1986.  Wuornos's first murder took place more than three years later, in November 1989, when she would have been aged 33 years to Moore's 27.

Comment
The timeline of the real life relationship has been compressed considerably in order to fit the screenplay.  The film also increases the age gap between the two characters, portraying Selby as a teenage girl led astray by a much older woman.  When Wuornos and Moore first met they would have been aged 30 and 23 respectively. 
 
The first killing
 
Film

Aileen's first killing is presented as an act of self-defence.  A john beats, binds and rapes Aileen before threatening to kill her.  Aileen manages to untie herself, grab her gun and shoot her attacker. 
 

Reality

In her confession, Aileen Wuornos claimed to have killed all seven of her victims in self-defence.  When she stood trial for the murder of her first victim, Richard Mallory, Wuornos claimed that she had shot him after he had tied her to the steering wheel of his car, raped her and announced his intention to kill her.  Wuornos's story did not stand up to cross-examination and the jury returned a guilty verdict.  Several months after the trial, it was discovered that Mallory had a conviction for a sex offence (housebreaking with intent to commit rape and assault, for which he had served five years in a psychiatric institution): information that appeared to support Wuornos's self defence claim.  However, in an appeal against the verdict, it was noted that if Wuornos's defence had used Mallory's conviction as evidence, it would have been considered too old to be relevant: Mallory had committed his crime more than thirty years before he encountered Wuornos.

Comment
There are four killings in Monster, the second, third and fourth of which are so loosely based upon the real life victims and events that they can be regarded as fictional.  By contrast, the first killing is clearly based on that of real life victim Richard Mallory, or, to be more precise, it is based on the version of events that Aileen Wuornos gave when tried for his murder. 
 
Looking for work

Film
Aileen tries to obtain a regular job but, due to her level of education and lack of an employment history, gets nowhere.

Reality
Aileen Wuornos, who was diagnosed with borderline personality disorder, found it extremely difficult to maintain her composure for any great length of time and was therefore ill suited to most forms of conventional employment.  Wuornos was understood to have had a few spells in regular jobs, but all were short-lived.

Comment
Monster illustrates Aileen Wuornos's difficulty in obtaining a job but it appears that her real problem was that of keeping one. 
 
Aileen's ability to ride a bicycle

Film
Aileen travels between job interviews on a bicycle and, for comic effect, has difficulty in riding it.

Reality
One of the published childhood photographs of Aileen Wuornos shows her, in her teenage years, astride a bicycle.  After settling in Florida, in her twenties, Wuornos's mode of transport was said to be a bike.  When, in her thirties, driving murder victim Richard Mallory's car to a remote spot in order to dump it, Wuornos took her bike along to enable her to ride home.  It can be safely assumed that Aileen Wuornos was a competent cyclist.

Comment
Monster sets out to highlight the vulnerable side of a notorious figure.  This is achieved, in part, by making her the butt of some jokes.  When Aileen admires herself in the mirror, voices her over-ambitious career plans or mispronounces Chablis, the makers of Monster are presenting her as a buffoon.  The slapstick cycling belongs in the same category, but would appear to be at odds with the reality. 
 
Aileen's criminal record
 
Film

In her final attempt at securing a regular job, Aileen visits an employment agency.  She admits to being a prostitute, which leads the agency representative to assume that she has been convicted of a felony. 

Reality

Aileen Wuornos had a lengthy criminal record which, surprisingly, did not feature any prostitution-related offences.  Prior to her murder trials, her most serious conviction was for armed robbery, for which she had served eighteen months in jail.  Wuornos's other convictions included common assault, grand theft auto and various firearms offences. 

Comment

Monster suggests that Aileen Wuornos's pre-murder criminal record consisted of nothing more than prostitution-related convictions.  In reality, Wuornos's record documented a long-established familiarity with theft and firearms. 
 
Aileen tells her partner about the first killing

Film
In an emotionally charged scene, Aileen tells Selby that she killed her last john.

Reality
In her courtroom testimony, Tyria Moore described the way in which Aileen Wuornos had told her about the killing of Richard Mallory: whilst watching television, Wuornos had calmly stated that she had shot and killed a man that day.

Comment
Sometimes, truth is stranger than fiction. 
 
Timeline (2)

Film
Aileen's first and second killings are separated in time by what appears to be no more than two weeks.

Reality
Aileen Wuornos's seven murders spanned twelve months, with a five month gap between the first and the second.

Comment
Monster suggests that Aileen's second killing came about as a direct result of the trauma induced in her by the events that led to the first.  This is achieved, in part, by distorting the real life timeline.  In reality, the greatest time gap between Aileen Wuornos's murders was that between the first and the second.

Gene: the stuttering john

Film
Aileen is all set to kill a john but, at the last moment, decides against it.

Reality
A few days after making her confession, Aileen Wuornos said the following in the presence of a prison officer. 

“I had lots of guys, maybe ten to twelve a day.  I could have killed all of them but I didn't want to. I'm really just a nice person.  I'm describing a normal day to you here, but a killing day would be just the same almost.” 

“On a killing day those guys always wanted to go way, way back in the woods, but I wasn't scared you know, 'cause they were always so nice.  I trusted them.  I mean, we went so far back in the woods that there weren't even any roads.  Now I know why they did it, they were gonna hurt me.” 

Also, Wuornos stole from all of her victims and it is understood that most, if not all, of them were carrying several hundred dollars in cash.

Comment

As regards the motivation behind Aileen Wournos's murders and the criteria that she used in the selection of her victims, this (entirely fictional) scene may get closer to the truth than any of the actual murders depicted in Monster.  The reason for Aileen's de-selection of Gene as a murder victim could be that, upon hearing him speak, she realises that he does not pose a threat to her, despite having driven her way, way back in the woods.  Alternatively, having seen the contents of his wallet, Aileen may have decided that Gene doesn't have enough cash to justify a killing. 
 
Aileen's childhood

Film
Immediately before crashing a car, Selby asks Aileen why she left home at such an early age.  Aileen claims that she and her siblings were left without a home after their father killed himself.

Reality
Aileen Wuornos never met her father and was abandoned by her mother.  When Aileen referred to her parents she actually meant her maternal grandparents, who adopted her.  When Aileen was fifteen years old, her adoptive mother/genetic grandmother died, an event that triggered the disintegration of the family unit.  Aileen was thrown out of the family home, had difficulty in finding accommodation and was often reduced to sleeping in abandoned cars.  Aileen's adoptive father/genetic grandfather committed suicide, but not until several years after Aileen's departure.

Comment
Aileen Wuornos could be creative when recalling her past and Monster may be depicting this aspect of her behaviour.  Alternatively, the film may be, pointlessly, fictionalising Aileen's history.  If the intention is to establish that Aileen Wuornos had a bad start in life, there is no need to deviate from the facts. 
 
The ending

Film
Selby leaves Aileen.  Aileen dumps her gun in a lake.  Aileen is arrested at The Last Resort bar.  Aileen telephones Selby from prison.  Selby tricks Aileen into confessing.  Aileen is tried for murder, with Selby as a prosecution witness, and is found guilty.

Reality
Tyria left Aileen.  Aileen dumped her gun in a lake.  Aileen was arrested at The Last Resort bar.  Aileen telephoned Tyria from prison.  Tyria tricked Aileen into confessing.  Aileen was tried for murder, with Tyria as a prosecution witness, and was found guilty.

Comment
With the exception of the part played by Bruce Dern's Tom (a fictional character) in the arrest scene, the last few minutes of the film stay true to the real life events. 
 
Conclusion
 
Whilst the last few scenes of Monster stick closely to the true story on which the film is based, the rest of the film features a hefty dose of dramatic licence.  It is probably unrealistic to expect Monster to provide a totally accurate account of Aileen Wuornos's crimes and life: as a drama, the film is primarily intended to entertain, rather than inform, its audience.

The real story of Aileen Wuornos is told in the following:

Feature length documentaries

Aileen: Life and Death of a Serial Killer (directed by Nick Broomfield and Joan Churchill, UK/USA, 2003)

Aileen Wuornos: The Selling of a Serial Killer (directed by Nick Broomfield, UK/USA, 1993)

Television documentary

Aileen Wuornos (Biography Channel, 2004)

Book

Lethal Intent by Sue Russell 
 

Another relevant book is Nick Broomfield: Documenting Icons by Nick Broomfield and Jason Wood, which features a chapter devoted to Broomfield's two documentaries on Aileen Wuornos.

Roger Burton