The dissertation Banzarov defended at Kazan in 1846, published as The Black Faith, or Shamanism among the Mongols, is a short book with a large claim. Russian and Chinese observers had treated Mongol religion as a residue, a disorder of superstition left behind by Buddhism or degraded from it. Banzarov argued that it was a religion in its own right with its own structure: heaven, Tengri, at the centre; the earth and its masters; the ancestral and clan spirits, the ongon; and a specialist whose work was defined by relations with all three.
He built the argument from Mongolian and Chinese written sources and from what he knew directly, and the phrase black faith is itself internal, the term used in Mongolian against the yellow faith of the Gelug monasteries. Working from a vocabulary the tradition used about itself, rather than from the categories of the observer, is what makes the book unusual for its date, and it is the reason it is still cited rather than only mentioned.
Parts of it have not aged well. The comparative framework is that of the middle of the nineteenth century and its evolutionary assumptions are visible on the surface. What survived is the basic move, that a religion should be described in terms it recognises, and later Buryat and Mongolian scholarship dates itself from him.