The concept of "lifestyle" is used in narrow (e.g., quality of sitting) and broad (e.g., Islamic prescriptive lifestyle model) senses in a variety of sciences such as sociology, medicine, clinical psychology, psychiatry, management, psychology, and so on. It is also viewed from the both perspectives of "beings and norms" and "musts and prescriptions". This books holds an extremely broad view to lifestyle by adopting the model prescribed by Quran and using the psychology and psychometric methodology and reports two types of research studies. The first type indicates the development and formation of a prescriptive model for the "Islamic lifestyle", and the second type proposes the development and psychometric assessment of "Islamic Lifestyle Test". The prescriptive model implies how the "Islamic lifestyle" is formed, on which attitudes it is established, and to what behaviors it leads in different life aspects. The "Islamic Lifestyle Test" reveals the extent of Islamic lifestyle for individuals and groups and shows in which components they are more powerful or less powerful. These two are complementary and have clinical, counseling, and selectivity applications.