Diary of a Murderer-The Mind Of A Sick Man

"Anyway, after that I called myself a poet. The way you feel about writing poems that no one reads and committing murders that no one knows about is not that different."

Diary of a Murderer is a novel by Korean author Kim Young-ha that delves into the mind of a serial killer suffering from Alzheimer’s, exploring it from a dark and psychological perspective. True to its name, this “diary”-style work shows us Kim Byeongsu, a former serial killer, as his memory gradually deteriorates due to Alzheimer’s and depicts his struggle with this decline.

As the story unfolds, we witness Byeongsu trapped between his past crimes and the present day, where he can no longer fully trust his own mind. Through the author’s storytelling, we feel this confusion firsthand. The words place us directly inside Byeongsu’s mind. He wants to protect his daughter, yet his own memories and instincts constantly make him suspicious, forcing him to question who the real threat really is. This leads him to act in ways he himself cannot fully understand.

From the first fifty pages, Young-ha prompts us to question human duality and lays bare the mind of a serial killer. What makes Diary of a Serial Killer unique is that it immerses the reader in a mind capable of horrifying acts while simultaneously eliciting empathy through the struggle with memory and identity.

As the book progresses, this creates an unsettling closeness to a criminal. Your mind can’t quite decide whether to connect with the main character or feel disturbed by his actions.

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"Byeongsu’s journey is both terrifying and heartbreaking. The young man he believes threatens his daughter’s life serves as a mirror reflecting Byeongsu’s former self. Forcing him and the readers to constantly question morality, justice, and perception. The plot you’ve constructed in your head can vanish in an instant, leaving you, like the main character, doubting the reality of events. The entire book plants the suspicion that everything might be a trick played by the protagonist’s own mind.

Toward the end, the story even makes you question whether his daughter is a real person or merely a hallucination, creating the concept of ‘real characters’ and ‘hallucination characters’ in our minds. This puts us, to some extent, in the protagonist’s shoes, while never letting us forget his struggle with Alzheimer’s.

Side characters like his daughter, who represents innocence and vulnerability, add tension and emotional depth to the story, making an already strong structure even more layered. We can’t be sure whether these characters truly exist; perhaps they are reflections of people the protagonist once knew, or killed.... This forces him to reevaluate the choices he has made throughout his life from a completely different perspective.

The psychological games, the lingering uncertainties until the very end, and the unreliable narration make every chapter full of unexpected surprises. A striking psychological exploration of memory, identity, and morality. Kim Young-ha’s Diary of a Murderer, is a quick, fast-paced read with a sharp edge.