Grupo Um is considered by critics one of the most daring, dense and radical sound experiments ever undertaken in Brazil. Formed in 1976 by pianist and composer Lelo Nazario and his brother, drummer and percussionist Z Eduardo Nazario, who at the time played in Hermeto Pascoal band, the group stood out as a leading representative of the vanguard arisen around the Teatro Lira Paulistana, combining the rhythmic richness of popular music with contemporary languages. This release features rare recordings from 1975.