Paul D. Simmons is a clinical professor in the Department of Family and Geriatric Medicine and an adjunct professor in the department of philosophy at the University of Louisville. He has written extensively on religion (specifically Baptist) and health care. He is the author of Freedom of Conscience: a Baptist and Humanist Dialogue (2000).

Stephen Bullivant directs the Benedict XVI Centre for Religion and Society at St. Mary’s University in London, where he also teaches the theology and sociology of religion. He previously served as co-director of the international Nonreligion and Secularity Research Network.

Frank Griffel is a professor of Islamic studies at Yale University. He wrote the chapter on agnosticism for the Encyclopedia of Islam (2004).

James Turner is the Cavanaugh Professor of Humanities at the University of Notre Dame. He is the author of Without God, Without Creed: The Origins of Unbelief in America (Johns Hopkins University Press, 1985).

Paul C. Vitz is a professor emeritus of psychology at New York University. He is the author of Faith of the Fatherless: The Psychology of Atheism.

Read an Oct. 23, 2012, Washington Post Guest Voices column about Kurtz by Herb Silverman, founder and president of the Secular Coalition for America.

Read the obituary posted by the American Humanist Association.

Read the obituary at the Center for Inquiry.

Read a May 24, 2010 Religion News Service story, about African-American atheists, “Blacks, Mirroring Larger U.S. Trend, ‘Come Out’ As Nonbelievers.”