The book is a discussion of Celtic fertility cults, comparing and contrasting with Isis / Cybele / Demeter etc, along the lines of Robert Graves's [not yet written at the time of this game] The White Goddess. It details various Celtic rituals described by Roman and other authorities, and identifies a common symbolic framework. However towards the end the author starts to extrapolate possible rituals of greater thematic efficiency than those used historically. He hints slightly elusively at a sort of ur-rite for contacting the great Mother-spirit requiring sacrifice - the more valued by society the victim, the more powerful the ritual.