Bob Dufford is a Jesuit priest and a well-known composer of liturgical music. He is best known for his composition "Sing to the Mountains," a popular hymn that has been widely used in religious services. The song is recognized for its uplifting and inspirational lyrics, making it a favorite in many church communities. Bob Dufford's contributions to sacred music have had a lasting impact, and his compositions continue to be cherished by those who appreciate his work in the realm of liturgical music.