There have been few bands in the twenty-first century that have been as thrillingly alive to the history of American music as the shapeshifting Portland, OR free rock ensemble Jackie-O Motherfucker. They paired folk with free jazz, post-rock with Protestant hymnody, New York minimalism with Negro spirituals. The sonic collective unconscious of the United States, in all its strangeness and suffering, seeped through their sound. A welcome twentieth anniversary reissue of their best-loved and most accessible album Flags of the Sacred Harp offers a fresh opportunity to reconsider their inimitable form of musical archaeology.