Jane Harrison examines the festivals of ancient Greek religion to identify the primitive "substratum" of ritual and its persistence in the realm of classical religious observance and literature. In Harrison's preface to this remarkable book, she writes that J. G. Frazer's work had become part and parcel of her "mental furniture" and that of others studying primitive religion. Today, those who write on ancient myth or ritual are bound to say the same about Harrison. Her essential ideas, best developed and most clearly put in the Prolegomena, have never been eclipsed.