Denny Randell (also a hit for The Spinners in 1979, and in Ireland for Boyzone in 1994), "Opus 17 (Don't You Worry 'Bout Me)", and, with Bob Crewe, "Let's Hang On!". Randell and Crewe later co-wrote Valli's solo hit "Swearin' To God". In 1965, Randell and Linzer wrote and produced most of the songs for the R&B girl group, The Toys, including their singles "A Lover's Concerto" (adapted from "Minuet in G major", a classical music piece), and "Attack!" Another Toys recording written by the duo, "Can't Get Enough Of You Baby", was later covered by the garage band ? and the
Switched-On Bach Invention in F major by Johann Sebastian Bach, which Carlos described as "charming". Soon after, Carlos began plans to produce an album of Bach pieces performed on a synthesizer, with the intention of using the novel technology to make "appealing music you could really listen to", not "ugly" music being produced by avant-garde musicians at the time. Elkind was impressed with the recording of Brandenburg Concerto No. 3 in G major and became the album's producer. Elkind contacted her friend, producer and conductor Ettore Stratta at Columbia Records, who "generously spread his enthusiasm throughout the rest of the company" and