This important study in religious psychology is intended to describe the processes by which an individual is converted, leaving aside the problem of grace. After a brief discussion of contemporary religious psychology and its scope and methods, it investigates the causes and the genesis of conversion, analyzes the different types of convert, examines sublimation, as well as the behavior of converts after conversion, and then discusses the possibility of the prediction of conversion in persons immune from insanity or neuropathic disease. It also studies the appearance of religious phenomena in persons who have never experienced these phenomena consciously.