Introduction
Both religion and spirituality (R/S) have played a major role in lives of human beings since the dawn of mankind and that remains the case in most cultures. Scientific literature shows a remarkable increase in high-quality research publications in the past decades providing insights and evidence-based information into the relationship between R/S and mental health. However, despite most mental health professionals acknowledging the importance of R/S issues in clinical practice, there has a been a large gap in translating this knowledge to clinical practice and professional training in mental health. Based on these unmet needs and on the robust available evidence, this book presents a comprehensive and sensitive review and summary of evidence and recommendations regarding R/S and mental health to inform clinical practice. Then a brief summary of the three sections (Theory, General principles of religions and relationship with mental health, and Clinical practice) and of the 25 chapter is presented.