Sally Moran of Charleston, S.C., is the author of a 2004 print-on-demand book, Women of the Covenant: The Case for Female Roman Catholic Priests.

Kenneth Carder is professor of the practice of pastoral formation at Duke University, Durham, N.C., and senior fellow of Pulpit & Pew. He is a United Methodist bishop.

Cynthia Woolever is director of U.S. Congregations in Louisville, Ky., a religious research group that is conducting the U.S. Congregational Life Survey.

Written by Kerry Walters. Walters gives an overview of the history and philosophy of Atheism.

Howard Hendricks is chairman of the Center for Christian Leadership at Dallas Theological Seminary in Texas.

Written by Robin Le Poidevin. Le Poidevin explains agnosticism as an ideology and writes about its history and development.

The Rev. Frederick W. Schmidt is director of spiritual formation and Anglican studies and an associate professor of Christian spirituality at Southern Methodist University, Dallas. He is the author of A Still Small Voice: Women, Ordination and the Church (Syracuse University Press, 1996).

Written by S.T. Joshi. Joshi writes about the history and development of modern Atheism.

William C. Placher is a professor of philosophy and religion and LaFollette Distinguished Professor in the Humanities at Wabash College in Crawfordsville, Ind. His books include, as editor, Callings: Twenty Centuries of Christian Wisdom on Vocation (Eerdmans Publishing, 2005).