Hugh B. Urban is Distinguished Professor of Comparative Studies at the Ohio State University, USA. He is the author of numerous books, including Secrecy (2021), The Church of Scientology (2010), Magia Sexualis (2005), and Tantra (2003).

Paul Christopher Johnson is Professor of History and Afroamerican and African Studies at the University of Michigan, Ann Arbor, USA. His books include Secrets, Gossip and Gods: The Transformation of Brazilian Candomblé (2002), Diaspora Conversions: Black Carib Religion and the Recovery of Africa (2007), and Automatic Religion: Nearhuman Agents of Brazil and France (2021).