Ksenofontov was born in 1888 near Yakutsk into a Sakha family of some means, studied law at Tomsk University, and practised before turning to ethnography. In the revolutionary years he took part in Sakha national politics, which is part of what later killed him.
His fieldwork belongs to the 1920s, a decade in which Soviet policy toward the peoples of the north still had room for national scholarship and native institutions. That window closed. In the 1930s the same policy turned to eradicating shamanic practice as a survival of class exploitation and to purging the national intelligentsias that had grown up in the 1920s. Ksenofontov was arrested and shot in 1938. His books were withdrawn from libraries and his name was dropped from citation.
The material survived along two routes. Copies of the 1929 and 1930 volumes were outside the Soviet Union and were used by western writers on shamanism, usually without much sense of what had happened to the author. Inside Russia he was rehabilitated late, and his work, including the large historical study of the origins of the Sakha, was republished at Yakutsk from the 1990s. He is now a national figure in the Sakha Republic. The sequence, a native scholar recording a practice, the state destroying both the practice and the scholar, and the notebooks returning as the principal evidence for what was destroyed, is the shape of a great deal of the Siberian record.