(written from a Production point of view)
Joel Marston (30 March 1922 – 18 October 2012; age 90) was an actor and dialogue coach who worked on the first four Star Trek films between 1979 and 1986. He received credit as "dialogue coach" in the end credits of Star Trek III: The Search for Spock. On Star Trek II: The Wrath of Khan, he also received credit as "Crew Chief" but was misspelled as Joel Marstan.  According to the call sheet for Star Trek III, dated Friday 2 September 1983, Marston also worked as stand-in on this film. Marston, who met William Shatner through their interest in dogs, worked as dialogue coach for Shatner on the first three Star Trek films.
Marston's acting career went over five decades. He started working in the 1940s with appearances in the crime comedy The Sky Dragon (1949, with Keye Luke), the music film Mississippi Rhythm (1949), the drama Forgotten Women (1949), the crime comedy Jiggs and Maggie in Jackpot Jitters (1949), and the romance There's a Girl in My Heart (1949).
Further acting work includes the music comedy The West Point Story (1950, with Chuck Courtney), the war drama Force of Arms (1951), the war drama The Red Badge of Courage (1951, with Whit Bissell, William Schallert, Arthur Tovey, and Shep Houghton), the crime drama F.B.I. Girl (1951), the drama Purple Heart Diary (1951), the Western Old Oklahoma Plains (1952), the comedy Just for You (1952, with William Meader and Julie Newmar), the war movie Battle Zone (1952), the war drama Flat Top (1952, with William Schallert), the crime drama The Steel Trap (1952, with Dick Crockett), the crime drama The Turning Point (1952, with Whit Bissell), the sport drama White Lightning (1953), the comedy The Girls of Pleasure Island (1953, with Hubie Kerns, Sr. and William Schallert), the science fiction thriller The War of the Worlds (1953, with William Meader, Reginald Lal Singh, and Arthur Tovey), the sport comedy The Caddy (1953, with Chuck Hicks, William Meader, and Arthur Tovey), the comedy Clipped Wings (1953), the sport drama Crazylegs (1953), the comedy Forever Female (1953, with Vic Perrin and Shep Houghton), and the war movie Fighter Attack (1953, with Kenneth Tobey, Anthony Caruso, Roy Jenson, and Morgan Jones).
Marston also appeared in episodes of Rebound (1952), Gruen Guild Playhouse (1952), The Cisco Kid (1952, with Troy Melton), Gang Busters (1952), Fireside Theatre (1952), General Electric Theater (1953), Dragnet (1953), The Pepsi-Cola Playhouse (1954), Space Patrol (1952-1954), Waterfront (1954), Treasury Men in Action (1955), Public Defender (1955, with Ron Gans), The George Burns and Gracie Allen Show (1954-1955, with John Hoyt), My Little Margie (1954-1955), Telephone Time (1956), Ethel Barrymore Theater (1956), Sally (1958), Matinee Theatre (1956-1958, with John Hoyt), Flight (1958), Boots and Saddles (1958), The Silent Service (1958), and Tales of the Vikings (1959).
He worked on the war drama Battle Taxi (1955), the crime drama The Night Holds Terror (1955), the crime drama Julie (1956), the horror film The Disembodied (1957), the crime drama The Gun Runners (1958), the crime drama The Decks Ran Red (1958), the crime drama The Fearmakers (1958, with Robert Fortier), and the drama Home Before Dark (1958, with Jean Simmons, Gail Bonney, and Chuck Hicks).
In the 1960s, Marston appeared in the action drama The Last Voyage (1960), the crime drama Ring of Fire (1961, with Frank Gorshin), the drama Harlow (1965, with Celia Lovsky, Nick Dimitri, Ron Gans, William Meader, and Arthur Tovey), and in episodes of Letter to Loretta (1960), Tales of the Vikings (1960), Bourbon Street Beat (1960, with George D. Wallace), The Law and Mr. Jones (1960, with Charles Drake, Robert Fortier, and Roy Jenson), Branded (1965, with Ian Wolfe and Bob Hoy), and The Lucy Show (1965-1966, with Lucille Ball, Keith Andes, Parley Baer, and Jack Perkins).
In the 1970s, he played Owen Stratton in the daily soap General Hospital (1974-1976) and worked on the horror drama Point of Terror (1971, with Dyanne Thorne), the fantasy romance Heaven Can Wait (1978, with Hamilton Camp, Keene Curtis, Morgan Farley, Ed Peck, Jim Boeke, and Robert Fortier), and the McMillan & Wife episode "Death Is a Seven Point Favorite (1971, with John Schuck, John Anderson, Dick Crockett, and Jack Perkins).
Besides his work on the Star Trek films, Marston also appeared on the television series Flamingo Road (1982, with John Beck and Paul Lambert). He then worked as dialogue coach on the television series The Love Boat. Between 1982 and 1986, he worked as dialogue coach for William Shatner on the television series T.J. Hooker, starring Shatner, Richard Herd, and James Darren. In addition, he was featured in two episodes in 1983 and 1986 (with David Froman, Nanci Rogers, Don Pulford, and David Zellitti on the latter one).
Following his acting career, Marston became internationally well-known as breeder of Chow Chows and proprietor of Starcrest Kennels in California. He also worked as long-standing water aerobic instructor in Jacksonville, Florida.  He passed away on 18 October 2012 at the age of 90 at his home in Jacksonville, Florida.