Kevin Lewis is a professor of religious studies at the University of South Carolina in Columbia. He teaches a course called “Visions of Apocalypse” and has written an essay on Americans’ obsession with the apocalypse.

Rebecca Denova is a lecturer in religious studies at the University of Pittsburgh in Pittsburgh, Pa., where she has taught a course called “Apocalypse Then and Now.”

Anthony Aveni is the Russell Colgate Distinguished University Professor of Astronomy and Anthropology and Native American Studies at Colgate University in Hamilton, N.Y., and author of The End of Time: The Maya Mystery of 2012.

Philip Lamy is professor of sociology and anthropology at Castleton State College in Castleton, Vt. He is an expert on secular millennial movements, including among survivalist groups and militias.

John J. Collins is a professor of Old Testament interpretation and criticism at Yale Divinity School in New Haven, Conn. He is an expert on Jewish apocalypticism.

Trish Maskew teaches adoption law, policy and practice at American University Washington College of Law. She founded Ethica, an adoption advocacy organization that works for ethical adoption practices internationally. She wrote Our Own: Adopting and Parenting the Older Child.

Randall L. Kennedy is the Michael R. Klein Professor of Law at Harvard Law School. He wrote Interracial Intimacies: Sex, Marriage, Identity and Adoption, an examination of the role of race in those arenas.

Heather Jacobson is assistant professor of sociology and anthropology at the University of Texas at Arlington. Her interests include sociology of families, the intersection of social inequality (race, class, gender) and families and family formation.

Marilyn Holt is a historian of American orphanages and an expert on the history of American Indian adoption. She wrote Indian Orphanages and The Orphan Trains: Placing Out in America.