May 16, 2005, 10:30 AM ET Jimmy Martin, one of the greatest vocalists in bluegrass, died Saturday (May 14) in a Nashville hospice where he was battling bladder cancer. He was 77. In 1949, Martin replaced Mac Wiseman in Bill Monroe's Blue Grass Boys, the premier bluegrass group, and served as the group's guitarist and lead vocalist until 1954. His tenor vocals were featured on many of the Monroe band's recordings for Decca -- perhaps most memorably on the gospel sides collected in 1969 on "A Voice From on High." After recording with the Osborne Brothers in the mid-'50s, Martin...