Ray Bradbury was an American author of 20th century science fiction.
The 1950s magazine Galaxy featured stories by Bradbury, as well as Robert Heinlein and Theodore Sturgeon. Herbert Rossoff believed that if he joined the magazine it would "complete" the lineup. (DS9: "Far Beyond the Stars")
The 24th century Federation starship Bradbury, and its class, were named in his honor. (TNG: "Ménage à Troi", "Brothers")
Ray Bradbury was asked by the production staff of the original Star Trek series if he wanted to contribute to the show. He visited the sets, but finally said no. (TOS Season 1 DVD special features)
The notion of Ray Bradbury writing for Star Trek was also suggested in a 2004 treatment for a new
Star Trek series, a fourteen-page document written by J. Michael Straczynski and Bryce Zabel. 
An article in the Los Angeles Herald Examiner on the premiere of the original series quotes Roddenberry as saying that "a future script of the series will be written by Ray Badbury."