Laura Engelstein's Castration and the Heavenly Kingdom: A Russian Folktale, published by Cornell University Press in 1999, is the standard scholarly account of the Skoptsy in English language historical writing. Engelstein, a historian of Russia, builds the book around a set of nineteenth century court records, the interrogation and trial of a Skoptsy community, preserved because the tsarist state periodically prosecuted the sect for the same practice of ritual castration its own members considered a mark of election for a promised heavenly kingdom.
The book's method is part of what makes it the field's reference point. Rather than treating the sect only as a curiosity, Engelstein reads the surviving testimony for what it can show about selfhood, the body and religious conviction in a peasant and merchant milieu the historical record rarely lets speak for itself. The Skoptsy did not write theology in the ordinary sense. They left interrogation transcripts, and Engelstein's study takes that unusual archive seriously as evidence of belief, not only as evidence of a crime.
The book has stood as the field's reference point since its 1999 publication, still the starting point any serious account of the sect returns to, because it treats the Skoptsy's own reasoning on its own terms rather than only as a case the tsarist state chose to prosecute. An outside academic study rather than a Skoptsy text itself, it remains the most careful reconstruction available of what adherents believed they were doing, and why.