Title: A Pup Named Scooby-Doo
Content:  Rock and roll-styled songs (specifically about the monster of the week) were played during the chase scene in each episode, similar to the second-season episodes of Scooby-Doo, Where are You! However, unlike previous versions of the show, the kids were often aware of the music being played (having turned it on themselves in many occasions) and would dance for a bit along with the ghosts and monsters before continuing with the chase (Glen Kennedy would often animate the characters' dance cycles himself). The show's theme song featured lyrics by series creator Tom Ruegger and music by composer John Debney also bore a similarity to the "Intro Song" from Little Shop of Horrors, which had recently been adapted into a successful feature film. The music is almost always in a 1950s rock and roll style, possibly to indicate their younger age, as the original show took place in 1969.
Title: Scooby-Doo
Content:  In the fall of 1972, new one-hour episodes under the title The New Scooby-Doo Movies were created; each episode featuring a real or fictitious guest star helping the gang solve mysteries, including characters from other Hanna-Barbera series such as Harlem Globetrotters, Josie and the Pussycats and Speed Buggy, the comic book characters Batman and Robin (later adapted into their own Hanna-Barbera series, Super Friends, a year later), and celebrities such as Sandy Duncan, The Addams Family, Cass Elliot, Phyllis Diller, Don Knotts and The Three Stooges. Hanna-Barbera musical director Hoyt Curtin composed a new theme song for this series, and Curtin's theme remained in use for much of Scooby-Doo's original broadcast run. After two seasons and 24 episodes of the New Movies format from 1972 to 1973, CBS began airing reruns of the original Scooby-Doo, Where are You! series until its option on the series expired in 1976.
Title: Scooby-Doo (film)
Content:  The film's score was composed by David Newman. A soundtrack was released on June 4, 2002, by Atlantic Records. It peaked at number 24 on the Billboard 200 and 49 on the Top R&B/Hip-Hop Albums. Shaggy performs the theme song from Scooby-Doo, Where Are You!, which was retitled "Shaggy, Where Are You?".
Title: Scooby-Doo, Where Are You!
Content:  The second season featured bubblegum "chase scene" songs produced by La La Productions (which had originally been contracted to create the music for Josie and the Pussycats, the first of many animated series made from the same mold as Scooby-Doo, Where Are You!). These songs were written by Danny Janssen and Austin Roberts, and were performed by Roberts, who also made a new recording of the Scooby-Doo, Where Are You! theme song for the second season. The series' theme song has been covered by several subsequent artists, including Matthew Sweet for the 1995 TV special and album Saturday Morning: Cartoons' Greatest Hits; Third Eye Blind for the 1998 film Scooby-Doo 
Title: Scooby-Doo's Snack Tracks: The Ultimate Collection
Content:  Scooby-Doo's Snack Tracks: The Ultimate Collection is the first and only soundtrack to the popular Hanna-Barbera Saturday morning cartoon franchise Scooby-Doo. The soundtrack consist of songs and theme songs from the incarnations produced from 1969 to 1985, from Scooby-Doo, Where Are You! to The 13 Ghosts of Scooby-Doo. Three songs, "Move Over", "Ruby Cool Guy" and "Gotta Have Time", were taken from the 1979 animated telefilm Scooby Goes Hollywood. A bonus track, called "Scooby's Mystery Mix", takes a majority of the sound bites included on the soundtrack as a musical mix. The sound bites featured on the soundtrack were taken primarily from the second season of Scooby-Doo, Where Are You!, but also from a few episodes of The New Scooby-Doo Movies, and features the entire cast from both series. Two guest stars from The New Scooby-Doo Movies, Jerry Reed and Davy Jones, appeared on the soundtrack singing the songs they performed in their guest-appearance episodes. The soundtrack was released on CD and cassette tape on September 15, 1998. It was later discontinued. The album peaked at number five on the Billboard Kids Album chart.
Title: Scooby-Doo 2: Monsters Unleashed
Content: 1) "Don't Wanna Think About You" by Simple Plan (Simple Plan had also performed the titular theme song) ; 2) "You Get What You Give" by New Radicals ; 3) "Boom Shack-A-Lak" by Apache Indian ; 4) "Thank You (Falettinme Be Mice Elf Agin)" by Big Brovaz ; 5) "The Rockafeller Skank" by Fatboy Slim ; 6) "Wooly Bully" by Bad Manners ; 7) "Shining Star" by Ruben Studdard ; 8) "Flagpole Sitta" by Harvey Danger ; 9) "Get Ready for This" by 2 Unlimited ; 10) "Play That Funky Music" by Wild Cherry ; 11) "Here We Go" by Bowling for Soup ; 12) "Love Shack" by The B-52's ; 13) "Friends Forever" by Puffy AmiYumi ; 14) "Scooby-Doo, Where Are You?" by MxPx A soundtrack was released on March 23, 2004, on compact disc and cassette tape. 
Title: Scooby-Doo
Content:  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 Don Messick as Scooby-Doo, Casey Kasem as Shaggy, Frank Welker as Fred, actress Nicole Jaffe as Velma, and Indira Stefanianna 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. Each of these episodes features Scooby and 
Title: Scooby-Doo
Content: Scooby-Doo: Don Messick was the original voice of Scooby-Doo from 1969 until 1996. Hadley Kay performed the voice for the Johnny Bravo episodes "Bravo Dooby-Doo" and "'Twas the Night", as well as in commercials, in 1997. Scott Innes was the voice of Scooby-Doo from 1998 to 2002. Neil Fanning voiced Scooby-Doo in the live-action Warner Bros. theatrical films produced in 2002 and 2004. Frank Welker is the current voice of Scooby-Doo, having taken over the role from Innes in 2002, although Innes voiced the character in video game projects (including PC, DVD and board games), commercials and some toys until 2008. Dave Coulier (2005) and Seth Green 
Title: Scooby-Doo (character)
Content:  Writers Joe Ruby and Ken Spears created the original Scooby-Doo series, Scooby-Doo, Where Are You!, for Hanna-Barbera for CBS's 1969–1970 Saturday morning cartoon schedule. Originally titled Mysteries Five, the dog who later became Scooby was originally more of a sidekick character – a bongo-playing dog named "Too Much" whose breed varied between Great Dane and sheepdog between treatments. By the time the series was pitched to the network as Who's S-S-Scared? in early 1969, Too Much was solidified as a cowardly Great Dane. Both the dog and the series would be renamed Scooby-Doo by Fred Silverman, CBS's head of daytime programming, between its unsuccessful first pitch and a second pitch, which earned the show a green light. Silverman stated that he came up 
Title: Scooby-Doo! Classic Creep Capers
Content:  still looked like settings from the series. Scott Innes, who was voice actor for Scooby and Shaggy at that time, provided his voice for the characters in the game. The original theme song from Scooby-Doo, Where Are You! was recreated for the game. The rest of the game's music – meant to be similar to music from the series – was created exclusively for the game. Because violence was never featured in the Scooby-Doo franchise, the game's designers had difficulty designing the gameplay in a way so that the player would have to either hide from enemies or move past them, rather than fight them. Various jokes from the series were implemented into the game. Development had concluded by October 2000, at which point the game was in Nintendo's final approval process.

Question: who sang the original scooby doo theme song?
Answer: Larry Marks.