The study discusses the correct name of one of Abd al-Abbas Iranshahri's books. The book is based on Bayan al-Adyan (بیان‌الادیان) authored by Abolma’ali Mohammad Balkhi, which has been called "Hastishenasi". Looking on the different meanings and interpretations of "Hasti" in Persian language and culture and the understanding of early scholars of Islam, the real name of the book seems to be "Hasti-Dad". It is emphasized in the study on the importance of Iranian's due attention to Persian and that many intellectuals found it necessary to have a heavenly book in Persian to explain and interpret the principles of Iran's historical and mythological beliefs. So, those who did not want a religion other than Islam in Iran, translated Qur'an, the holy book of Islam, into Persian in the Samanid period.