The volume edited by Kioanoosh Rezania brings together seventeen articles by Philip Kreyenbroek on the subject of Zoroastrianism. The collection represents the author's most important short contributions on that subject, written over a period of more than 30 years. Although the papers are concerned with a range of different subjects, they are to some extent interconnected, and in several cases, one may find lines of argument emerging in one article which the author develops in subsequent papers. The papers cover six important aspects of Zoroastrianism: History; the Zoroastrian tradition and its oral transmission; Cosmology, Cosmogony and Eschatology; Priesthood; and Ritual. Topics discussed there include the history of the Zoroastrian tradition in various periods; the mainly oral nature of the Zoroastrian religious tradition until well into the Islamic period, and some of the implications of this for our understanding of that tradition; Kreyenbroek's views and hypotheses on the nature and origin of the Indo-Iranian and Zoroastrian cosmogonies; the various developments in the structure of the priesthood, particularly during and after the Sasanian period; and lastly various questions concerning the Zoroastrian ritual, which are informed by the author's extraordinary familiarity with the Zoroastrian ritual literature.