John Collins Dawson IV, nicknamed "Marmaduke", was an American musician, singer, and songwriter. He was best known as the leader and co-founder of the country rock band the New Riders of the Purple Sage. He sang lead vocals on most of the band’s songs.

New Riders of the Purple Sage is an American country rock band. The group emerged from the psychedelic rock scene in San Francisco in 1969 and its original lineup included several members of the Grateful Dead. The band is sometimes referred to as the New Riders or as NRPS.