This book is a multi-faceted study of the Sros Dron, comprising chapters 3 to 8 of the Yasna ceremony, the core ritual of the Zoroastrian religion. It provides a critical edition produced with the electronic tools of the project The Multimedia Yasna, and a study of the performative aspects of the Sros Dron both through the lens of the ritual directions and in comparison with the Dron Yast ceremony. By analysing the Sros Dron both as a text attested in manuscripts and as a ritual performance, Celine Redard applies a new approach to unlock the meaning of these chapters of the Yasna.