Jean Kellens, one of the foremost experts on Old Iranian literature for the last quarter of a century, is professor at the Collège de France, Paris. He began his Iranian studies with Professor Jacques Duchesne-Guillemin at Liège, Belgium, in the 1960s before going to Erlangen, Germany, to continue his education in Old Iranian and Old Indic literatures with Professor Karl Hoffmann. Here he obtained his Ph.D. with a thesis on the Avestan root nouns. From 1974 to 1980 he was the assistant professor to Professor Helmut Humbach at Mainz, Germany, where he finished his Habilitation thesis on the Avestan verb. He continued his career as assistant professor and then full professor at the University of Liège from 1983 to 1993, when he went to Paris. He has dedicated his career to the elucidation of the most difficult of ancient literature, the Avesta, the holy book of the old Iranian Zoroastrians. Between 1988 and 1991 he published together with Eric Pirart a scholarly edition and translation of the oldest texts in the Avesta, including the Gathas ascribed to Zarathustra, that laid the foundation for modern work on these texts. Since that time he has continued to refine our knowledge of both these texts and the younger Avestan texts.
This book contains a series of articles from the period 1987 to 1994 plus the four lectures he gave at the Collège de France in 1990, which encompass Kellens's most important work on the Old Avesta. The English translation of this work is intended to make it accessible to the larger audience it deserves, including students of Old Iranian and Indic, as well as Indo-Europeanists and historians of religion.

Prods Oktor Skjærvø, translator and editor of the volume, has written extensively on a variety of aspects of Iranian civilization, from modern dialects, via Sasanian inscriptions and Khotanese Buddhist texts from Central Asia, to Old Persian and Avestan. He currently teaches Old Iranian languages, literature, and religions at Harvard University in Cambridge.