Original director John Barry had made his name as a set designer, and had been acclaimed for his work on Star Wars: Episode IV - A New Hope (1977) and Superman (1978). After he was removed from this movie, he was working as a second unit director on Star Wars: Episode V - The Empire Strikes Back (1980) when he collapsed on-set and died of meningitis.
Hector the robot stood over eight feet tall, and cost a little over $1 million to make.
Kirk Douglas thought the clothes he wore in this movie were so comfortable that he kept them after production wrapped.
Elmer Bernstein wrote an hour of music for this movie, much of it progressive and experimental, but most of it was unused after the opening sequences until the movie's last half hour. Bernstein removed some of the cues after the movie was extensively re-edited, because they did not work in truncated form, while others appear to have been removed by producer and replacement director Stanley Donen. The full score was released as a very Limited Edition CD in 2008, that is now out-of-print.