*What's Happening!! aired 3 seasons, 1975-1979 (it began as a summer series), and 65 episodes on ABC. As we mention, the spinoff/sequel What's Happening Now!! actually lasted 66 episodes.
*Doobie or Not Doobie is a two-parter from middle of the series' second season, premiering January 28 and February 4, 1978.
*Here is a link to our Love Boat episode, in which we discuss the very show that followed this What's Happening!! in 1978.
*Here is the TV Party article on the history of What's Happening!!
*The 1975 Cooley High film was a smash before inspiring the loose adaptation in the TV series. The first version was a single-camera dramatic pilot, but Fred Silverman suggested retooling it into the format that became popular.
Wikipedia claims that the movie also inspired The White Shadow, and many websites repeat that, but the only source I can find for that tidbit is one solitary Huffington Post article on Erykah Badu, who is a big fan of the film.
*I personally think that Henry Mancini's theme song for the show ranks among his best work right along with The Pink Panther and Moon River.
*The Doobie Brothers did not appear in What's Happening Now!!
*As Mike alludes to, Doobie guitarist Skunk Baxter is a missile defense expert--and a self-taught one, no less! Read this great piece from Business Insider to learn his story. The article mentions Baxter was a reserve police officer in the L.A. area. I'd like to think his frontier justice approach to apprehending Al Dunbar in the episode inspired his entry into law enforcement.
*Fred Berry, who was part of the dance group The Lockers, died at 52 in 2003.
*For more on the strange death of brief semi-regular Ray Vitte, look at this article. Vitte died in police custody under mysterious circumstances after a conflict with the cops.
*The same website explored the departure of Mabel King from the series, using comments from Ernest Thomas. Essentially, she disliked the stereotypical maid role she had and departed when she was unable to influence the creative direction.