If you enjoyed The Cannibal Within, the author recommends five books for twisted souls:
 
Earth Abides by George R. Stewart.
 
Science suggests that 75,000 years ago, because of a global catastrophe, the human race may have reduced to as few as 4,000 people-- with just 500 females of childbearing age.
 
In Earth Abides, a global virus repeats the mass extinction.   Even the lice, adapted to man, go extinct.
 
 
 
Invasion of the Body Snatchers by Jack Finney
 
Psychiatrists have something they call Capgras Syndrome, a condition in which someone becomes convinced that a familiar person has been replaced by an identical replica.  But, what if loved ones are being replaced?
 
Justine by the Marquis de Sade. 
 
The Marquis de Sade, who spent 27 of his 74 years in prisons or insane asylums, asked to be buried in a forest in an unmarked grave strewn with acorns.
 
In our species, baby boys are sometimes born with erections—and Justine features the horror of toxic masculinity--brutes making weeping girls orgasm. 
 
 
The Tragical History of Doctor Faustus.
Christopher Marlowe.
 
 
Jeffrey Burton Russell noted that Johann Faust, who was a real person, is the single most popular character in the history of Christianity after Christ, Mary, and the devil. 
 
The author, Christopher Marlowe, was stabbed in the eye and killed at the age of 29.  Traditionally, that was the death of someone who has seen too much.
 
Joseph Conrad. The Heart of Darkness. 
 
Set in colonial Congo, where a plumber from Europe could become a warlord, an ivory merchant, a big  game hunter, a master of a harem—or a psychopath.