This episode was one of John Erman's earliest jobs as a director and depicts Earth soldiers who have been captured and are being tormented by aliens on a mostly barren set, consisting of a few rock-like props and doorways. It bears many striking similarities to The Empath (1968), also directed by Erman, in which Kirk, Spock, McCoy and the titular empath Gem, played by Kathryn Hays, spend the majority of their screentime on a mostly bare set consisting of a few props and dark curtains, also being tormented by aliens. Willard Sage appeared in both episodes, playing the Chief of Staff in this episode and Thann, one of the alien tormentors, in that episode.
This episode was originally scheduled to be shown on November 25, 1963. However, it was delayed for one week due to the coverage of the state funeral of President John F. Kennedy.
The poem that Major Jong recites while he is being tortured ("Oh friend grasshopper... Will you play... The caretaker... To my little grave?") is a haiku by the late-18th century Japanese poet and Buddhist priest Kobayashi Issa.
The facial and hand prosthetics worn by John Anderson as the Ebonite Interrogator in this episode were later reused for the Anderan Senator in Fun and Games (1964).