Björn Mastiaux has written his Master’s thesis in sociology on the secularization debate with an emphasis on the rational choice approach within the sociology of religion. He is employed as a research and teaching assistant at the Institute for Social Sciences at Heinrich Heine University Düsseldorf, Germany. For his PhD, he is conducting an exploratory study on members of atheist, freethought, or secularist organizations in Germany and the United States. His teaching and research interests include general sociological theory, qualitative research methods, sociology of religion, and sociology of social movements.