1st edition: November 2018 Positive Psychology is the scientific study of human happiness. It emphasizes the study of positive emotions, positive personality traits, and positive institutions, in an effort to complement the issues addressed by clinical psychology and psychotherapy, which usually focus on negative emotions and mental illness. It is the newest and perhaps the fastest-growing branch of psychology, because its principles, basic concepts, axioms, and emerging theories are compatible and complementary with the major theories of psychology. It seems that Positive Psychology can enrich the existing theoretical and conceptual models concerning psychotherapeutic change and is compatible with most therapeutic approaches. The authors of the book focus on how Positive Psychology comes to complement, expand, and consequently improve existing psychotherapeutic models, demonstrating that it can and has room to be integrated into traditional theoretical models concerning psychotherapeutic change and the way it is achieved, as well as to enrich clinical practice with new tools. The main questions posed are: • In what way can Positive Psychology enrich our understanding of the process of psychotherapeutic change? • What therapeutic interventions can be integrated into different psychotherapeutic models to improve and increase their effectiveness? • What are the central elements of Positive Psychology that help the psychotherapist in clinical work? • In what way does the integration of Positive Psychology concepts help us better understand human nature, the process of change, and the process of healing psychological wounds? Aspiring to fill a gap in the literature on psychotherapy, the book is aimed at students of psychotherapy and counseling, clinical psychologists, psychotherapists, and those who practice or are about to practice psychotherapeutic work, significantly contributing to the dialogue regarding the search for common therapeutic factors, the synthesis of therapeutic models, and the improvement of therapeutic practices.