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
Following the success of the original series, Hanna-Barbera and its successor Warner Bros. Animation have produced numerous follow-up and spin-off animated series and several related works, including television specials and made-for-TV movies, a line of direct-to-video films, and two Warner Bros.–produced theatrical feature films. Some versions of "Scooby-Doo" feature different variations on the show's supernatural theme, and include characters such as Scooby's cousin Scooby-Dum and nephew Scrappy-Doo in addition to or instead of some of the original characters.