This non-fiction book explores the phenomenon of gratitude from the perspective of positive psychology - as a source of strength for our mental health and a fulfilling life. Research in emotions has revealed in recent years that nothing benefits our mental well-being as much as the lasting feeling of genuine gratitude. The book illustrates what gratitude is, where it derives its power from, and how it can be learned. Since the author is well-versed in the disciplines of psychology, philosophy, and theology, and works as a trainer and coach, the reader uncovers the secret of gratitude in a multidimensional, profound, yet practical way. Discover the source of power of this wonderful emotion, whose significant importance for the health of society and individuals has been known since time immemorial, but is only now gaining increasing awareness due to the shift towards positive psychology.