Unusual for a movie of its time, this features two highly contentious subjects. One is that characters are clearly seen smoking marijuana. The other is that there are two mixed-race relationships featured, and neither of them warrants a mention. [Note: Although mixed-race relationships were still, in 1961, illegal in several parts of the United States, they emphatically did not carry the same stigma in Britain that they did in the U.S.] In addition, there is the strong (though unspoken) hint that Johnny is a repressed homosexual whose marriage is probably still unconsummated and whose hatred of Aurelius Rex stems from frustrated sexual desire.
Screenwriter Paul Jarrico, who had been blacklisted, used the name "Peter Achilles" when the film was originally released, The Writers Guild of America West restored Jarrico's credit for this film and three others in 1998. Betsy Blair, who plays Emily, also fell prey to the House UnAmerican Activities Committee. Gene Kelly, her husband at the time, intervened to get her the part in Marty (1955) for which she earned an Academy Award® nomination, but she eventually had to move to Europe to pursue her career.
Dave Brubeck, who appears in the film, said, "My contract for the film specified I would not play with Charles Mingus, because I knew how demanding Charlie could be and I just wanted to avoid it. It was out of respect. And fear." Mingus, though, kept bugging the director to play with Brubeck, so the pair ended up playing a Mingus composition, "Non-Sectarian Blues." Brubeck noted, "When it was over, Charlie picked me up off the floor and gave me a bear hug. It was wonderful."