Daniel Keyes, who has died aged 86, was a writer who was most famous for his disturbing science-fiction novel Flowers for Algernon which tells the story of a janitor with learning difficulties whose intelligence is boosted by surgery. It was a novel of great pathos and skill, with the style of writing changing as Charlie Gordon's IQ increases.
The novel, first published in 1959 and twice made into a film, has never gone out of print and has been widely translated and studied in schools and colleges around the world. Cliff Robertson won an Oscar for his role in the first movie version Charly in 1968.
The novel was also adapted as a stage play and was performed all over the world. It was also developed as a musical in the 1970s starring Michael Crawford and performed at the Queen's Theatre in London's West End.
Born in New York, where his father ran a junk shop, Keyes joined the US maritime service when he was 17 years old and served as ship's purser. After leaving the navy, he resumed his studies at Brooklyn College where he received his BA degree in psychology.
He then worked in publishing as a fiction editor before taking up fashion photography and also working as an English teacher. While teaching during the day and writing fiction at weekends, he returned to Brooklyn College as a postgraduate student to study English and American literature. His first published short story, Robot Unwanted, appeared in Other Worlds in 1952.
After receiving his MA degree, he left New York to teach creative writing at Wayne State University.
He joined the faculty of Ohio University in 1966, was appointed professor of English and creative writing, and in 2000 was honoured with professor emeritus status. Brooklyn College awarded Keyes Distinguished Alumnus Medal of Honour in 1988.
As well as Flowers for Algernon, Keyes wrote four other novels. There was The Touch (in 1968) dealing with the human tragedy connected with a radiation accident, and The Fifth Sally, the first novel to deal with multiple personality disorder.
There was also Until Death, a novel dealing with a double homicide in Florida and the issue of competency for execution, and most recently, The Asylum Prophecies, which was published in 2009.
In addition, Keyes published three non-fiction books. The Minds of Billy Milligan was about the first criminal trial to deal with the plea of multiple personality disorder. It was followed by a sequel The Milligan Wars.
He also wrote In Unveiling Claudia, which explored the mystery behind a woman's false confession to three of the ten 22-Calibre Murders.
In his 2000 memoir, Algernon, Charlie and I: A Writer's Journey, Keyes explored the life experiences and events that led to the creation of Flowers for Algernon. He explained that it was teaching students struggling with literacy that gave him the idea for the novel. He said he met a boy who was unhappy being in the class. "He wanted to be smart," said Keyes.
But Keyes also admitted that, successful though it was, he sometimes found it hard to move on from the novel. "Charlie is haunting me," he wrote. "I try to put him out of my mind, but he won't let me." The same year the memoirs were published, another movie version of the book was made starring Matthew Modine and Kelli Williams.
Keyes is survived by his two daughters. His wife Aurea died last year.