This is the now classic attempt to identify the mysterious god / plant / substance of the Sanskrit Vedas as the fly agaric mushroom, a fungus known to have mood-altering hallucinogenic properties when properly prepared and consumed. Wasson argues that the cryptic descriptions of the Soma can be explained by the shape and colors of the mushroom, while its effects explain its association with divine powers, and its use in the sacrificial rituals to contact the gods. The conclusion has been widely accepted, and bitterly disputed, with a number of opponents returning, armed with new information, to earlier proposals.

The earlier views are the subject of a substantial section of this thick volume, a survey of the nineteenth and twentieth century literature by Wendy Doniger O'Flaherty, who is now writing as Wendy Doniger. In later writings, Doniger has supported more strongly Wasson's conclusion that Soma was originally a fungus, although admitting to some uncertainty as to which fungus, and to whether the sacred species might have shifted with time and availability. This survey is in itself a useful reference, and Doniger's translations of the some of the Rig-Veda Soma Hymns in her selection from "The Rig-Veda" for the Penguin Classics is a helpful companion as well.

(For the full set of such hymns, I know of only one English version, R.T.H. Griffith's aging complete translation of the Rig Veda -- second edition 1896 -- which, among other problems, accepted Max Mueller's identification of Soma with the Ephedra plant. The theory would make more sense if the species Mueller named was in fact the pharmacologically active Ma Huang variety, instead of just a relative.

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Soma: Divine Mushroom of Immortality, (Ethno-Mycological ...