George Clayton Johnson, the science fiction novelist, TV scriptwriter and comic book creator best known for co-writing the 1967 novel Logan’s Run, died Friday of cancer. He was 86.

Johnson’s son Paul posted this on Facebook:

My Father, George Clayton Johnson, passed away this Christmas day at 12:46 p.s.t. He was more than a reknowned writer, fan & hemp legalization advocate, he was a truly loving father & huband. His wife, Lola Johnson daughter, Judy Olive & I, his son, Paul B. Johnson mourn his loss. The outpouring of love from all of you has sustained us during this difficult time. In around 30 days I’ll post the info on a “lifetime celebration” party that we’ll hold in his memory. If all my friends who see this post will repost it to their friends, word will get out faster & I would be most appreciative. He loved his family, friends, but he had a special place in his heart for all of his fans, who sustained him & gave him a forum to share thoughts at a million miles a second…

Born in Cheyenne, WY, in 1929, Johnson dropped out of school in the ninth grade and spent his early adulthood as a draftsman following service in the U.S. Army and a brief stint in college. He broke into writing as a profession in 1959 penning the Alfred Hitchcock Presents episode “I’ll Take Care of You.” During this period, he sold a short story that later would serve as the basis for the Rat Pack film Ocean’s 11.

Soon after, he was accepted into the Southern California School of Writers, a Los Angeles-based who’s who of authors whose work would become hugely influential on American popular culture — among them Theodore Sturgeon, William F. Nolan, Charles Beaumont, Richard Matheson and Ray Bradbury. Through his association with the group he met Twilight Zone creator Rod Serling, selling him a story that would serve as the basis for the episode “The Four of Us Are Dying.” This led to a lengthy association with the show; Johnson ultimately would write either the stories or teleplays for eight episodes of the anthology series, among them the classics “A Game of Pool” and “Kick The Can” The latter was adapted for the Steven Spielberg-directed segment in 1983’s Twilight Zone: The Movie.

Johnson’s other television contributions include episodes of Route 66, The Law and Mr. Jones and Kung Fu.

Johnson also has the distinction of providing crucial contributions to two of the most important science fiction works from the era, both in 1967. First was his script for “The Man Trap”, the first-aired episode of the original Star Trek. The episode sees the crew of the Enterprise encountering and forced to kill a shape-shifting parasite that is the last of its kind. Although not considered the official first episode of the series, it did set the tone for episodes to come and is notable for themes that would recur later.

That same year, Johnson collaborated with William F. Nolan on the novel Logan’s Run. Admitting later that the two were trying to write something they knew would sell, they spent a couple of weeks banging out the story that tapped into then-current anxieties about the generation gap. Set in a dystopian future in which people are summarily executed upon reaching the age of 21, the story follows an operative tasked with eliminating those who try to escape the system, who ends up fleeing it himself. It was adapted into the 1976 film starring Michael York that moved the age of execution up to 30.

Johnson also co-created the comic series Deepest Dimension Terror Anthology. In later life, he became a dedicated activist for the legalization of marijuana. He lived in Los Angeles at the time of his death.