Quicksilver Messenger Service, like many of the '60s San Francisco psychedelic bands, were assembled from disparate parts that few would have guessed would have been compatible. In Quicksilver, Duncan and drummer Greg Elmore emerged from the teen garage rock scene. Both had been in the Brogues, though Duncan (born Gary Grubb), wasn't in the band when they did their first single in 1965. Under the name Gary Cole, he joined the Brogues in the summer of 1965 and was in the band when they recorded their second and last single, which paired a fine sullen version of "I Ain't No Miracle Worker" (better known as done by the Chocolate Watch Band) and "Don't Shoot Me Down" (in the style of one of Duncan's favorite bands, the Pretty Things). In late 1965, the Brogues broke up and Elmore and Duncan moved from Merced to San Francisco to join Quicksilver Messenger Service.
On Quicksilver's first two albums, Duncan also contributed some vocals and co-wrote standout songs like "Light Your Windows," "Gold and Silver," and "The Fool." However, Duncan left at the end of 1968, frustrated by what he felt was the band's lack of motivation to expand their repertoire and write new songs. In 1969, he tried to form bands with his good friend Dino Valenti, who had been planning to be in the group that became Quicksilver Messenger Service before getting busted, before Duncan was involved in the project (and before Duncan had even met Valenti). At the end of 1969, though, Duncan ended up rejoining Quicksilver and Valenti got in the band as well. The band radically changed in character as Valenti took a heavy role in the singing and songwriting, and Cippolina and David Freiberg left over the course of their early '70s albums, which were less impressive than those of the previous decade. Valenti and Duncan kept the band going through much of the '70s, but by the end of the decade, Duncan left music for a while to work as a longshoreman for a few years.
Duncan was the sole remaining member of the vintage Quicksilver -- as their name had now been shortened to -- when Peace by Piece came out in 1986. He has remained active in the music since, sometimes as the principal in Quicksilver. ~ Richie Unterberger, Rovi