Mark Edward Ruff is professor of history at Saint Louis University. A historian of religion and modern Europe, he has written widely on secularization, church-state relations, and the history of the churches under Nazi rule. He is the author of two monographs, including The Wayward Flock: Catholic Youth in Postwar West Germany, 1945 - 1965, and the coeditor of two collections of essays. He also serves as a church organist.