James Fowler’s (1981) Stages of Faith has inspired theory and research in the U.S.A. and worldwide to interpret and analyze the developmental changes of individual religiosity. ‘Faith development’ has become the term for a specific structural-developmental perspective which originates in Fowler’s work and which enjoys increasing recognition in the psychology of religion. Because of the roots of Fowler’s (1981) model in the tradition of Piaget and Kohlberg, faith development research was, especially in the early years, searching for evidence of the new structural-developmental model of religious development which ambitiously has claimed consistency with Kohlberg’s (Kohlberg, Levine & Hewer, 1983) criteria for stage models. Today, since plausibility for the structural-developmental paradigm has declined and most colleagues in the field have become rather unenthusiastic with a priori presuppositions for conceptualizing ‘hard stage development,’ theory and research in religious development can be understood – less burdened with presuppositions and empirically more effective – as accounting for and measuring of individual differences in religious styles. Conceptualizing religious development in terms of religious styles and schemata opens new perspectives, qualitative and quantitative. New instrument development and new empirical evidence in the years 2009 and 2010 add to the advancement of the new model.