The Vendidad, more precisely the Videvdad, meaning the law against the demons, is the Avesta's priestly law code. Its twenty two fargards, or chapters, work through the sources of ritual pollution the tradition takes most seriously, above all contact with the dead, and prescribe purification procedures in close procedural detail: how long isolation must last, what a person may and may not touch, and how a corpse should be handled to limit the pollution it is held to spread.
The code is not purely legal. Fargard 2 carries a narrative distinct from anything else in the Avesta, the story of Yima, a legendary king warned by Ahura Mazda of a coming catastrophic winter and instructed to build a vara, an enclosed shelter, in which to preserve pairs of every kind of living thing until the danger passes. Read alongside other flood and winter survival narratives across Indo-European traditions, the Yima story gives the Vendidad a mythic register that its procedural chapters otherwise lack, and it is the passage most often discussed outside specialist study of the text.
Because its subject is law rather than liturgy, the Vendidad is used differently from the Yasna: consulted and applied rather than recited as an ongoing ceremony.