The Zend Avesta, translated and interpreted by James Darmesteter, is a foundational work for the study of Zoroastrianism, one of the world’s oldest known religions. Darmesteter’s scholarly edition, first published in the late nineteenth century, played a crucial role in introducing Western readers to the sacred texts of ancient Persia and in shaping modern understanding of Zoroastrian theology, ritual, and cosmology. The Avesta is a collection of religious writings attributed to Zoroaster (Zarathustra) and his followers. It includes hymns, prayers, liturgical formulas, and mythological narratives that articulate the central principles of Zoroastrian belief: the cosmic struggle between truth (asha) and falsehood (druj), the moral responsibility of human choice, and the ultimate triumph of good. Darmesteter’s work focuses especially on the later Avestan texts, often called the “Zend,” providing translation alongside historical and philological commentary. As a leading Orientalist of his time, Darmesteter approached the Avesta not only as a religious scripture but also as a historical and cultural document. His introduction and notes explore the development of Iranian religious thought, the interaction between myth and ritual, and the influence of Zoroastrian ideas on later religious traditions, including Judaism, Christianity, and Islam. While later scholarship has revised some of Darmesteter’s interpretations, The Zend Avesta remains an important milestone in comparative religion and Indo-Iranian studies. It reflects both rigorous academic inquiry and a deep respect for the spiritual heritage of ancient Iran. This work is essential reading for students of religion, mythology, and ancient history, offering insight into a belief system that profoundly shaped concepts of ethics, dualism, and cosmic order in the Western and Eastern worlds alike.