One of the most striking developments in the history of modern civilizations has been the conversion of tribal peoples to more expansively organized "world" religions. There is little scholarly consensus as to why these religions have endured and why conversion to them has been so widespread. These essays explore the phenomenon of Christian conversion from this world-building perspective. Combining rich case studies with original theoretical insights, this work challenges sociologists, anthropologists and historians of religion to reassess the varieties of religious experience and the convergent processes involved in religious change.