This short book is comprised of selected teachings of Zoroaster (Zarathustra). The author himself was a member of the Indian Zoroastrian community. The teachings in the book cover Commandments for the Body and Soul, the Soul's destination, a Gatha hymn, prayer of Kem Na Mazda, prayer of Ormuzd Yast, the creation of the world and God's warning to Yima.
Source and copyright Global Grey Ebooks: https://www.globalgreyebooks.com/index.html. The book can be downloaded from the Global Grey website.