Because of his back problems and his difficulty walking, the screenplay was written so that Boris Karloff could perform his role while seated in a wheelchair.
The central premise is reminiscent of a film that Boris Karloff made three decades earlier. In The Invisible Ray (1935) ("Universal") he plays a scientist who is experimenting with a radioactive meteor that causes him to glow dangerously and ultimately burn to ashes.
The train station at which Stephen Reinhart (Nick Adams) disembarks is called Arkham. Arkham was a fictional town created by H.P. Lovecraft.
In 1965 American-International Pictures distributed this film in the US on a double bill with the Italian sci-fi film Planet of the Vampires (1965), which was dubbed in English and re-titled "Planet of the Vampires".
A contemporary article in "Daily Variety" noted this was the first "monster" role for Boris Karloff in 30 years.