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.

Daniel Wojcik is a professor of folklore studies at the University of Oregon. He is interested in contemporary American apocalyptic movements and groups, especially those focused on UFOs.

Sharan Newman is the author of The Real History of the End of the World: Apocalyptic Predictions From Revelation and Nostradamus to Y2K and 2012.

Simon Martin is a Mayanist scholar and senior research specialist at the University of Pennsylvania Museum of Archaeology and Anthropology, known as the Penn Museum. Martin is co-curator of an exhibit there titled “Maya 2012: Lords of Time,” and he is co-author of Chronicle of the Maya Kings and Queens: Deciphering the Dynasties of the Ancient Maya.

Jonathan Kirsch is the author of A History of the End of the World: How the Most Controversial Book in the Bible Changed the Course of Western Civilization. He says apocalyptic anxiety has never been wholly absent from our culture, but it is at an all-time high now, due to current events and natural disasters.

John R. Hall is a professor of sociology at the University of California, Davis. He is the author of Apocalypse: From Antiquity to the Empire of Modernity (2009) and can discuss the history of apocalyptic movements, prophets and groups.

Crawford Gribben is a director of the Trinity Millennialism Project at Trinity College in Dublin, Ireland.

Joseph Gelfer is an adjunct research associate in the School of Political and Social Inquiry at Monash University in Australia and editor of the anthology 2012: Decoding the Countercultural Apocalypse (2011).

Stephen C. Meyers is president of the Institute for Biblical and Scientific Studies and a critic of Harold Camping.