Charles Campbell is Professor of Homiletics at Duke Divinity School. He is the coauthor with Johan Cilliers of Preaching Fools: The Gospel as a Rhetoric of Folly (2012).Charles Campbell is Professor of Homiletics at Duke Divinity School. He is the coauthor with Johan Cilliers of Preaching Fools: The Gospel as a Rhetoric of Folly (2012).