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.
Animation in the United States in the television era
Hanna-Barbera was notorious for using common tropes in its series. Its original series of the late 1950s through mid-1960s all featured anthropomorphic animals, usually an adult (who would in turn impersonate a well-known celebrity) and child, interacting with the humans of their environment. After the immense success of "Scooby-Doo, Where Are You!", which premiered on CBS in 1969, the next decade of Hanna-Barbera's animated output would follow that show's formula: a group of teenagers solving mysteries or fighting crime, usually with the help of a wacky animal or a ghost. The many incarnations of "Scooby-Doo" ran uninterrupted on CBS and then ABC for 17 seasons. During the late 1970s and early 1980s, Hanna-Barbera turned to adaptations of prime time sitcoms. It was not until "The Smurfs" in 1981 that H-B once again had anything successful outside the "Scooby" template; it, in turn, led to derivative series ("The Snorks" and "Paw Paws"). The late 1980s and early 1990s saw Hanna-Barbera join the numerous studios producing younger and junior versions of cartoon characters for the Saturday morning cartoon market.