In the tradition of a repertory theater company, each episode featured predominantly the same ensemble of guest actors, cast as different characters in each episode/story.
In part 1 of "Prisoner's Base," Archie's paycheck reveals his weekly salary ($200) and Wolfe's address (914 West 35th Street). Both of these are well known by all loyal readers of Rex Stout's books, which are written in the first person by Archie Goodwin who, as a good investigator, records every detail that concerns himself and his employer.
Conrad Dunn plays the recurring role of Saul Panzer throughout the series except for the first case, The Golden Spiders, where that role was played by Saul Rubinick. Rubinick switched to the recurring role of newspaperman Lon Cohen for the rest of the series.