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.
The New Scooby and Scrappy-Doo Show
For this incarnation of the show, Hanna-Barbera attempted to combine the most successful elements of both the original "Scooby-Doo, Where Are You!" format and the newer "Scooby-Doo and Scrappy-Doo" format. Daphne Blake, a character from the original "Scooby-Doo, Where Are You!" format, was added back to the cast after a four-year absence. The plots of each episode feature her, Shaggy Rogers, Scooby-Doo, and Scrappy-Doo solving supernatural mysteries under the cover of being reporters for a teen magazine. Each half-hour program was made up of two 11-minute episodes, which would upon occasion be two parts of one half-hour-long episode.