Bundahishn
Bundahishn, meaning "Primal Creation", is the name traditionally given to an encyclopædiaic collections of Zoroastrian cosmogony and cosmology written in Book Pahlavi. The original name of the work is not known.
Although the Bundahishn draws on the Avesta and develops ideas alluded to in those texts, it is not itself scripture. The content reflects Zoroastrian scripture, which in turn reflects both ancient Zoroastrian and pre-Zoroastrian beliefs. In some cases, the text alludes to contingencies of post-7th century Islamic Iran, and yet in other cases (e.g. in the idea that the moon is further away than the stars) reiterates scripture even though science had by then determined otherwise.
Structure
The traditionally given name seems to be an adoption of the sixth word from the first sentence of the younger of the two recensions. The older of the two recensions has a different first line, and the first translation of that version adopted the name Zand-Ākāsīh, meaning "Zand-knowing", from the first two words of its first sentence.