Le "Nerangestan", ou "Livre d'indication rituelles" vient, dans les manuscrits, a la suite du "Herbedestan" mais represente un texte a part qui a essentiellement trait a l'education religieuse. Les deux textes appartiennent a la tradition savante du Zoroastrisme, et les longs passages du commentaire pehlevi sont souvent plus eclairants que le sont les phrases laconiques en avestique. Toujours est il que peu de passages sont faciles a lire parce que la plupart des iranistes occidentaux ont une connaissance peu approfondie des differents rituels zoroastriens, tandis que l'objectif du "Nerangestan" etait d'elucider des points qui semblaient obscurs meme aux pretres pratiquants de l'epoque. Le deuxieme Fragard du "Nerangestan" est fonde sur l'enseignement de Sosans, mais n'a probablement ete consigne dans sa forme actuelle que plusieurs generations apres ce grand commentateur. C'est de loin le chapitre le plus long du texte, et la richesse d'informations qu'il contient procure de nouveaux apercus dans differents aspects de la vie religieuse et rituelle de la communaute zoroastrienne.The "Nerangestan", the "Book of Ritual Directions", follows the "Herbedestan" in the manuscripts but is in fact a separate text, dealing with matters of ritual where the "Herbedestan" is mainly concerned with religious education.
Both texts belong to the learned tradition of Zoroastrianism, and the lengthy passages of Pahlavi commentary are often more illuminating than the terse Avestan sentences. Still, few parts of the text make easy reading; most Western Iranists have at best a passing acquaintance with the various Zoroastrian rituals, while the "Nerangestan" was intended to elucidate points which seemed obscure even to the practising priests of its time. The Second "Fragard" of the "Nerangestan" is based on the Teachings of Sosans, but was probably written down in its present form several generations after this great Commentator. It is by far the longest extant chapter of the text, and the wealth of information it contains affords new insights into several aspects of the religious and ritual life of the Zoroastrian community.