There are three reasons given why we have to pay attention to the psychology of religion: there are phenomena in religion we have to understand as psychologists; there are religious people we come in contact with as psychologist in the praxis and there are believing psychologists we cannot completely understand without paying attention to their faith. The main part of the article tries to define several basic terms: religion and esp. christian religion, belief, faith, psychology of faith etc. There is an overview of the history of the psychology of religion and a look at the present state of it. The most studied topics of psychology of religion are reviewed: coming to faith (metanoia), quest, maturation of faith, pastoral care, overt and covert signs of faith. Some 20 different methods used in the psychology of religion are reviewed and recommended further literature given.