Shiva and Dionysus?
Looking at still another book by Danielou, Gods of Love And Ecstasy, The Traditions of Shiva and Dionysus, which continues the themes demonstrated here in some of the selections.
But I think this approach fails to distinguish between historical analysis, and the embrace in almost cultic fashion of very ancient religious forms.
Actually, we can hardly know what those sources really were.
But the basic point appears sound: there is a substrate still visible of very ancient religous forms going back to the Neolithic.
Whether this is really connected with Dionysus, or whether the languages said to be related really are (e.g. Sumerian. Dravidian, Basque, et al.) is less clear.