Cook's co-compositions have included "You've Got Your Troubles", and the transatlantic million-selling songs, "I'd Like to Teach the World to Sing"[2] and "Long Cool Woman in a Black Dress".

Continuing on as a duo, Cook and Greenaway then had a brief but successful recording career between 1965 and 1967 as David and Jonathan, scoring hits with a cover version of the Beatles' "Michelle", and their own "Lovers of the World Unite".

The group was formed in 1969, primarily as a producer's outfit, featuring a wealth of top session musicians including Herbie Flowers (bassist), Alan Parker (guitarist), Roger Coulam (keyboardist) and Barry Morgan (drummer),[8] who were simultaneously members of the jazz / rock / big band fusion outfit CCS, another mainly recording act.

[1] Amongst hits he has written with others, including Greenaway and writers such as Albert Hammond, Mike Hazlewood and Tony Macaulay are "I'd Like to Teach the World to Sing" (The New Seekers), "Good Times, Better Times" (Cliff Richard), "Softly Whispering I Love You" (The Congregation), "Something's Gotten Hold of My Heart" (Gene Pitney), "Home Lovin' Man" (Andy Williams), "Blame It on the Pony Express" (Johnny Johnson and the Bandwagon), "Something Old, Something New" (The Fantastics), "Conversations" and "Something Tells Me (Something's Gonna Happen Tonight)" (Cilla Black), "I've Got You on My Mind", "My Baby Loves Lovin'" (White Plains), "Gasoline Alley Bred" and "Long Cool Woman in a Black Dress" (The Hollies); "Freedom Come, Freedom Go" (The Fortunes), "Doctor's Orders" (Sunny), "I Was Kaiser Bill's Batman" (Whistling Jack Smith) and "Like Sister and Brother" (The Drifters).

[10] In 1975 Cook moved to the US and settled in Nashville, Tennessee, where he produced more hits including "Talking in Your Sleep" (Crystal Gayle in 1978, first recorded by Marmalade) and "Love Is on a Roll" (Don Williams).