The robots created for this episode were recycled by the BBC for an episode of Doctor Who (1963) entitled "The Mind Robber".
This episode was wiped by the BBC and no copy of it is known to exist.
The character of Dr Susan Calvin had also appeared in another Asimov story, "Little Lost Robot", in the 1962 ITV anthology series "Out of the World", and appears again in Season Three episode, "Liar!".