Marc von der Ruhr is an associate professor of economics at St. Norbert College in De Pere, Wis. He is interested in the economics of religion, and megachurches are the focus of several of his research projects.

Joseph P. Daniels is an economics professor at Marquette University in Milwaukee. He co-authored a paper that presented an economic model of “religious investment” to explain how seeker-oriented megachurches attract and keep members.

Bill Day is a professor at New Orleans Baptist Theological Seminary and associate director of its Leavell Center for Evangelism and Church Health. His areas of specialization include evangelism and church growth.

Lizette Beard is project manager for LifeWay Research, where she has coordinated projects about megachurches and multisite churches. LifeWay is affiliated with the Southern Baptist Convention and is based in Nashville, Tenn.

Sandra Barnes is a professor of human and organizational development at Vanderbilt University in Nashville, Tenn., whose research interests include the sociology of religion. She is the author of The Black Mega Church: Framing and Addressing HIV/AIDS and Poverty in the Age of Health and Wealth Theology.

Os Guinness is an author and social critic who lives in McLean, Va. His books include Dining With the Devil: The Megachurch Movement Flirts With Modernity. He is a senior fellow at the EastWest Institute in New York City.

Carl George is a church-growth consultant and coach who lives in Taylors, S.C.

Kimon Sargeant is vice president of human sciences at the John Templeton Foundation in West Conshohocken, Pa. Sargeant likens megachurches to shopping malls in his book Seeker Churches: Promoting Traditional Religion in a Nontraditional Way.

Robert Putnam is the Malkin Research Professor of Public Policy at Harvard University, where he studies civic connectedness, social capital, and religion and public life. He is author or co-author of more than a dozen books, including The Upswing: How America Came Together a Century Ago and How We Can Do It Again and Bowling […]