(written from a Production point of view)
Byron Conrad "Bun" Haskin (22 April 1899 – 16 April 1984; age 84), was a director, writer, and producer who worked in the motion picture and television industry from the early 1920s through the late 1960s.
Haskin started out as a newspaper cartoonist, then became a commercial-industrial and newsreel cinematographer in the 1920s. He soon turned to special effects photography, and worked in Hollywood as a special effects designer for nearly twenty years. Later he went on to direct mostly science fiction and fantasy films (often in collaboration with legendary producer/director George Pal), including such classics as The War of the Worlds (1953), The Naked Jungle (1954, with Abraham Sofaer), Conquest of Space (1955) and From the Earth to the Moon (1958). In the late-1940s, and early-1950s he also directed several Walt Disney productions, including the classic Tresure Island (1949). Between 1963 and 1964 he directed six episodes of The Outer Limits, including "Demon with a Glass Hand", with Arlene Martel and Abraham Sofaer, written by Harlan Ellison.
In 1964, he served as associate producer on "The Cage". According to his successor, Robert H. Justman, he and Gene Roddenberry didn't get along well, explaining why Haskin was not in Star Trek beyond the original pilot.  Furthermore, Justman adds that Haskin always argued with Roddenberry on the special effects. He frequently pointed out that Roddenberry's ideas were unfeasible, but Roddenberry pushed him to stick to them, which led to frequent arguments. (Inside Star Trek: The Real Story, p 34).