Books
- Science Marches On: The novel The Last Woman in His Life contains some extremely outdated psychological ideas regarding homosexuality. Unfortunately, some of these ideas are integral to the solution of the mystery.
TV Series
- California Doubling: For the most part set in New York City, but like most US series of its time was filmed in the greater Los Angeles area. It only really shows in daytime scenes, where you can see Manhattan streets baking in the desert sun.
- Fake American: In an unusual recursive example, in "The Adventure of Auld Lang Syne", British actress Joan Collins plays an American social climber... who adopts a British accent as an affectation, thus allowing the actress to speak in her natural accent.
- Fake Nationality: The very British Roddy McDowall as the Amazing Armitage in "The Adventure of the Black Falcon", affecting the most godawful German accent ever. The example is zig-zagged, however, as his character is revealed to be an American who is only pretending to be German; characters in-universe even comment on how phony his accent is.
- Missing Episode: The two-hour telemovie was left out of most syndication packages. For many fans, their first chance to see it was on DVD.
- Playing Against Type: Tom Bosley, best known as the genial patriarch of the Cunningham clan in Happy Days, playing a Mean Boss in "The Adventure of the Comic Book Crusader".
- Stunt Casting: Guy Lombardo as the bandleader in a club where a murder takes place on New Year's Eve.
- You Look Familiar:
- Barbara Rush played Emma Zelman in "The Adventure of Auld Lang Syne" and Claire Mallory in "The Adventure of the Sinister Scenario" playing two separate characters.
- Herb Edelman played a cab driver in "The Adventure of Auld Lang Syne" and a television writer in "The Adventure of the Hard-Hearted Huckster".
