The Bielefeld-based Cross-cultural Study on “Spirituality” has been inspired by the previous Bielefeld-based Cross-cultural Study on Deconversion. In this chapter we review this previous study and highlight the open questions and desiderata for the present study. Linking the two research perspectives implies the interesting question: Does “spirituality” and biographical development toward “spirituality” involve processes of deconversion? Because both are changes in the religious field that are associated with the “spiritual” self-attribution, our model of the religious field may help to understand this link. Where is privatized, experi-ence-oriented religion located in the religious field?