Question: Who had more novels adapted into films, Alan Sillitoe or Walter Van Tilburg Clark?

Context paragraphs:
The Watchful Gods and Other Stories: The Watchful Gods and Other Stories is a collection of short stories by Walter Van Tilburg Clark published in 1950.  It brings together eight stories and one novella (the title story).  Three of the stories had already appeared in the annual anthology of O. Henry Award-winning stories, most notably "The Wind and the Snow of Winter" which was selected by that anthology, in 1945, as their "first-place winner."  Since this book's publication, two other stories have remained notable: "The Portable Phonograph" and "Hook" have both been widely anthologized since they were published.

Alan Sillitoe: Alan Sillitoe (4 March 192825 April 2010) was an English writer and one of the so-called "angry young men" of the 1950s.  He disliked the label, as did most of the other writers to whom it was applied.  He is best known for his debut novel "Saturday Night and Sunday Morning" and early short story "The Loneliness of the Long Distance Runner", both of which were adapted into films.

The Loneliness of the Long-Distance Runner: "The Loneliness of the Long-Distance Runner" is a short story by Alan Sillitoe, published in 1959 as part of a short story collection of the same name.  The work focuses on Smith, a poor Nottingham teenager from a dismal home in a working class area, who has bleak prospects in life and few interests beyond petty crime.  The boy turns to long-distance running as a method of both an emotional and a physical escape from his situation.  The story was adapted for a 1962 film of the same title, with Sillitoe writing the screenplay and Tony Richardson directing.  The part of Smith (now called Colin) was played by Tom Courtenay.

The Ox-Bow Incident (novel): The Ox-Bow Incident is a 1940 western novel by Walter Van Tilburg Clark in which two drifters are drawn into a lynch mob to find and hang three men presumed to be rustlers and the killers of a local man.

The City of Trembling Leaves: The City of Trembling Leaves (1945) is a novel in the semi-autobiographical genre, by Walter Van Tilburg Clark.  The novel is a series of parallel narratives detailing the lives and work of a group of redacted characters named Tim Hazard, Lawrence Black, Mary Turner, Rachel Wells, Marjory Hale, "Walt", (the narrator) and assorted other side-characters.

The Ragman's Daughter: The Ragman's Daughter is a 1972 British crime–drama romantic film directed by Harold Becker and adapted by Alan Sillitoe from his short story of the same name.  It was Becker's first film during the 1970s and stars Simon Rouse and, in her screen debut, Victoria Tennant.  The film tells the story of the ill-fated love between Tony, a petty thief from a working-class family, and Doris, the daughter of an upwardly mobile scrap dealer.

Saturday Night and Sunday Morning (film): Saturday Night and Sunday Morning is a 1960 British drama film directed by Karel Reisz and produced by Tony Richardson.  It is an adaptation of the 1958 novel of the same name by Alan Sillitoe, who also wrote the screenplay adaptation.  The film is about a young machinist who spends his weekends drinking and partying, all the while having an affair with a married woman.

Walter Van Tilburg Clark: Walter Van Tilburg Clark (August 3, 1909 – November 10, 1971) was an American novelist, short story writer, and educator.  He ranks as one of Nevada's most distinguished literary figures of the 20th century, and was the first inductee into the 'Nevada Writers Hall of Fame' in 1988.  Two of his novels, "The Ox-Bow Incident" and "The Track of the Cat," were made into films.  As a writer, Clark taught himself to use the familiar materials of the western saga to explore the human psyche and to raise deep philosophical issues.

Key to the Door (novel): Key to the Door is a novel by English author Alan Sillitoe, first published in 1961.

Track of the Cat: Track of the Cat is a 1954 film directed by William A. Wellman and starring Robert Mitchum and Teresa Wright.  The film is based on a 1949 adventure novel of the same name by Walter Van Tilburg Clark.  This was Wellman's second adaptation of a Clark novel, the first being "The Ox-Bow Incident".  "Track of the Cat" was produced by John Wayne and Robert Fellows for their Wayne/Fellows production company.

Supporting paragraphs: Alan Sillitoe Walter Van Tilburg Clark
Answer: Walter Van Tilburg Clark