This article presents the results of a qualitative study initiated by the Enquete Commission of the 13th German Parliament on 'So-called Sects and Psychogroups'. Narrative interviews with members and ex-members of Christian-fundamentalist groups in Germany were conducted, selected according to the rule of maximal contrast, and interpreted using sequence analysis and narrative analysis. Our study yielded the following results: a typology of Christian-fundamentalist biographies, including an unexpected type which we have called 'accumulative heretic;' insights into the motivational impact of specific life themes which lead to, or impede, a certain 'fit' between the convert and the intellectual, ritual and moral setting of the respective group; and discernment of the indication of transformation and development during and after membership in Christian-fundamentalist milieus. A framework of religious styles is suggested to understand the formation and transformation of fundamentalist orientation.