Over twenty years after this episode first aired, actress Kathryn Harrold - who plays a psychologist in this episode - trained in psychology and began running her own counseling practice in Los Angeles.
Leo Gordon, who portrays bodyguard Charles 'Charlie' Martell, was a recurring guest star as Big Mike McComb in five episodes of James Garner's 1950's series Maverick (1957).
When Jim goes to check out Danny Green, the address - 11558 Riverside Drive, in Los Angeles, is actually, a real apartment building, which still has lanterns on squared cement posts out front. It's a residence, named 'The Marquis'.
This is one of the very few times - especially for older TV shows - to show a residence, which not only is real, but, all information given (on the show) about it (building and street number), are real, as well.
Usually, a ficticious address (such as the Ricardo's Manhattan address on I Love Lucy, being 623 E. 68th St.) is given, for several reasons, most importantly, is hoping to avoid unwanted fans showing up.
When we first see Roger in the recording studio, the man giving him voice-directions is played by Peter Tomarken, who's best-known as a game show host, whose hosting gigs included Press Your Luck (1983).
The handwriting expert is played by Allan Arbus, who had a recurring role on M*A*S*H (1972) as army psychiatrist Major Sidney Freedman.