Award-winning fantasy and speculative fiction writer Harlan Ellison died today at the age of 84.

Born May 27, 1934 in Cleveland, Ohio, Ellison is considered one of the most prolific science fiction authors during his time, writing 1,700 short stories, novellas, screenplays, essays and articles.

He wrote scripts for television shows such as The Outer Limits, The Man from U.N.C.L.E., and Star Trek, and won a slew of awards including multiple Hugos, Nebulas and Edgars.

He is famous for writing the Star Trek episode “City on the Edge of Forever,” in which Captain Kirk allows the woman he loves to die in order to correct the timeline. "City on the Edge of Forever" won several awards and is widely acknowledged as the best episode of the entire franchise.

Susan Ellison has asked me to announce the passing of writer Harlan Ellison, in his sleep, earlier today. “For a brief time I was here, and for a brief time, I mattered.”—HE, 1934-2018. Arrangements for a celebration of his life are pending.

— Christine Valada (@mcvalada) June 28, 2018

Ellison was editor and anthologist for two science fiction anthologies, Dangerous Visions (1967) and Again, Dangerous Visions (1972).

He was hired as a writer for Walt Disney Studios but was fired on the same day after making jokes about making a pornographic animated film featuring Disney cartoons.

He also served as creative consultant to the 1980s version of The Twilight Zone science fiction TV series and Babylon 5.

Several writers and artists have spoken out about their admiration for Ellison, including horror writer Stephen King.

"There was no one quite like him in American letters, and never will be. Angry, funny, eloquent, hugely talented. If there's an afterlife, Harlan is already kicking ass and taking down names," King wrote on Twitter.

Harlan Ellison: There was no one quite like him in American letters, and never will be. Angry, funny, eloquent, hugely talented. If there's an afterlife, Harlan is already kicking ass and taking down names.

— Stephen King (@StephenKing) June 28, 2018

Author and comic book writer Warren Ellis also reminisced about the time he asked Ellison why he had to pick a fight "over every little thing."

I once asked Harlan Ellison how many books and stories he hadn't had time to write because he just had to fuck around and pick a giant fight over every little thing.

He said, "Sure, but you can't let the bastards get away with it."

— Wᴀʀʀᴇɴ Eʟʟɪs (@warrenellis) June 28, 2018

Writer Isaac Asimov, meanwhile, tweeted an excerpt from Dangerous Visions on his first encounter with Ellison at the World Science Fiction Convention.

"The story of how I came to meet Harlan Ellison." (3 images)

Rest in Peace pic.twitter.com/R0xw3L1mWZ

— Isaac Asimov (@isaacasimov) June 29, 2018