Yasna (Avestan for 'oblation' or 'worship') is the name of the primary liturgical collection of texts of the Avesta as well as the name of the principal Zoroastrian act of worship at which those verses are recited. The Yasna, or Izeshne, is primarily the name of the ceremony in which the entire book is recited and appropriate liturgical actions performed. In its normal form, this ceremony can only be performed in the morning.