(written from a Production point of view)
Jim Goodwin (21 May 1929 – 18 May 1980; age 50) was an actor whose career was a small body of work stretched over almost two decades, from 1961 through 1979. In that time, he had small roles in two films and a dozen television guest appearances, three of which were in Star Trek: The Original Series as John Farrell.
Goodwin was a personal friend of Star Trek associate producer / story editor John D.F. Black, who got him his small roles on the show. Originally, Goodwin (and the character of Farrell) would have appeared in more episodes. But he was written out from both "The Naked Time" (where he was replaced by Lieutenant Kevin Riley (Bruce Hyde)) and "Charlie X". After Black's departure from the series, Goodwin left as well. (These Are the Voyages: TOS Season One)
Goodwin filmed his scenes for "Mudd's Women" on Thursday 2 June 1966, Friday 3 June 1966, Tuesday 7 June 1966 and Wednesday 8 June 1966. He filmed his scenes for "The Enemy Within" on Thursday 16 June 1966. He filmed his scenes for "Miri" on Tuesday 30 August 1966. He filmed all his scenes for the series on Desilu Stage 9.