Holy Organ or Unholy Idol? focuses on the significance of the cult of the Sacred Heart of Jesus and its accompanying imagery in eighteenth-century New Spain. Lauren G. Kilroy-Ewbank considers paintings, prints, devotional texts, and archival sources within the Mexican context alongside issues and debates occurring in Europe to situate the New Spanish cult within local and global developments. She examines the iconography of these religious images and frames them within broader socio-political and religious discourses related to the Eucharist, the sun, the Jesuits, scientific and anatomical ideas, and mysticism. Images of the Heart helped to champion the cult’s validity as it was attacked by religious reformers.