Starring: Robert Conrad, Dick Cangey, Ross Martin, Whitey Hughes
The Night of the Infernal Machine - S2-E14
Continuity mistake: As the toy bear is making its way to Gordon, in the background to the right of the window is a plant on a wooden stand. Next to it is a full length long green curtain with gold tassled fringe at the bottom. Gordon throws the toy bear through the window, but there is no glass breaking. The tall wooden plant stand now is wrapped inside the curtain, and the golden fringe cannot be seen. (00:28:10)
The Night of the Avaricious Actuary - S4-E11
Continuity mistake: The letter from the Cyclops Insurance Company that Gordon pulls out of his pocket is folded, wrinkled, and well-worn. In the close up of the same letter West reads, the letter is white, pristine, and not wrinkled or folded.
The Night Dr. Loveless Died - S3-E4
Trivia: Dr. Loveless' uncle's name, "Liebknicht", is, aside from the addition of the letter "k", German for "Loveless".