The Grass Roots was originated by the writer/producer team of P.F. Sloan and Steve Barri as a pseudonym under which they would release a body of Byrds/Beau Brummels-style folk-rock. Sloan and Barri were contracted songwriters for Trousdale Music, the publishing arm of Dunhill Records, which wanted to cash in on the folk-rock boom of 1965. Dunhill asked Sloan and Barri to come up with this material, and a group alias under which they would release it. The resulting "Grass Roots" debut song, "Where Were You When I Needed You," sung by Sloan, was sent to a Los Angeles radio station, which began playing it. The problem was, there was no "Grass Roots." The next step was to recruit a band that could become the Grass Roots. Sloan found a San Francisco group called the Bedouins that seemed promising on the basis of their lead singer, Bill Fulton. Fulton recorded a new vocal over the backing tracks laid down for the P.F. Sloan version of the song. The Bedouins were, at first, content to put their future in the hands of Sloan and Barri as producers, despite the fact that the group was more blues-oriented than folk-rock. However, the rest of the group was offended when Fulton was told to record their debut single, a cover of Bob Dylan's "The Ballad of a Thin Man," backed by studio musicians. When that single, released in October of 1965, became only a modest hit, the Bedouins -- except for their drummer, Joel Larson -- departed for San Francisco, to re-form as the Unquenchable Thirst. Sloan and Barri continued to record.
Amid the machinations behind Where Were You When I Needed You, no "real" Grass Roots band existed in 1966. A possible solution came along when a Los Angeles band called the 13th Floor submitted a demo tape to Dunhill. This group, consisting of Warren Entner (vocals, guitar, keyboards), Creed Bratton (lead guitar), Rob Grill (vocals, bass), and Rick Coonce (drums), was recruited and offered the choice of recording under their own name, or to take over the name the Grass Roots, put themselves in the hands of Sloan and Barri, and take advantage of the Grass Roots' track record. They chose the latter, with Rob Grill as primary lead vocalist. The first track cut by the new Grass Roots in the spring of 1967 was "Let's Live for Today," a new version of a song that had been an Italian hit, in a lighter, more up-tempo version, for a band called the Rokes. "Let's Live for Today" was an achingly beautiful, dramatic, and serious single and it shot into the Top Ten upon its release in the summer of 1967. From: https://www.allmusic.com/artist/the-grass-roots-mn0000070773#biography
