Contemporary psychology is highly influenced by positivism and scientific naturalism. Psychological studies make efforts to control the variables and provide operational definitions of subjective constructs in order to reach the most concrete conclusions. Such efforts are admirable in natural sciences since they have led to a better life. But, this worldview has deprived contemporary psychology of more qualitative sources of knowledge like waḥy (revelation). The present book introduces Islamic psychology as a paradigm, which can apply waḥy knowledge and consider religious/spiritual dimensions of humans in scientific exploration. The first part discusses the possibility, foundations, and characteristics of Islamic psychology. The second part introduces research methodology in Islamic psychology. The third part reviews the Quranic theory of personality and highlights the concept of shakeleh . Finally, the fourth part presents the theories and methods of religious psychotherapy in the Islamic tradition. Each part provides introductory content for readers interested in Islamic psychology.