Scooby-Doo
The first episode of "Scooby-Doo, Where Are You!" "What a Night for a Knight" debuted on the CBS network Saturday, September 13, 1969. The original voice cast featured veteran voice actor Don Messick as Scooby-Doo, radio DJ Casey Kasem (later host of radio's syndicated "American Top 40") as Shaggy, actor Frank Welker (later a veteran voice actor in his own right) as Fred, actress Nicole Jaffe as Velma, and musician Indira Stefanianna Christopherson as Daphne. Scooby's speech patterns closely resembled an earlier cartoon dog, Astro from "The Jetsons" (1962–63), also voiced by Messick. Seventeen episodes of "Scooby-Doo Where are You!" were produced in 1969–70. The series theme song was written by David Mook and Ben Raleigh, and performed by Larry Marks.
Scooby-Doo
"Scooby-Doo" was originally broadcast on CBS from 1969 to 1975, when it moved to ABC. ABC aired the show until canceling it in 1986, and presented a spin-off featuring the characters as children, "A Pup Named Scooby-Doo", from 1988 until 1991. New "Scooby-Doo" series aired as part of Kids' WB on The WB Network and its successor, The CW Network, from 2002 until 2008. "Scooby-Doo! Mystery Incorporated" aired on Cartoon Network from 2010 to 2013, and "Be Cool, Scooby-Doo!" aired on Cartoon Network from 2015 to 2018. Repeats of the various "Scooby-Doo" series are broadcast frequently on Cartoon Network's sister channel Boomerang in the United States as well as other countries.