Not only the title, but the plan and a good deal of the incidental symbolism of the poem were suggested by Miss Jessie L. Weston's book on the Grail legend: From Ritual to Romance (Cambridge). Indeed, so deeply am I indebted, Miss Weston's book will elucidate the difficulties of the poem much better than my notes can do; and I recommend it (apart from the great interest of the book itself) to any who think such elucidation of the poem worth the trouble. To another work of anthropology I am indebted in general, one which has influenced our generation profoundly; I mean The Golden Bough; I have used especially the two volumes Adonis, Attis, Osiris. Anyone who is acquainted with these works will immediately recognize in the poem certain references to vegetation ceremonies.
The Exploring The Waste Land site has more information about The Golden Bough by Sir James George Frazer.
There are also more pages about the divinities mentioned by Frazer: