In this introductory chapter, we provide an overview of The Handbook of Stress and Mental Health. We begin by introducing the scope of the issue and critically operationally defining the construct of stress. We then provide a description of the chapters included in the volume, as well as an outline of the purpose of each of the five major sections: Assessment and Definitional Issues, Stress Exposure and Mental Health, Psychological Models, Neurobiological Models, and Stress Resilience and Treatment. The contributors represent international leaders in the field of stress and provide authoritative and integrative review and analysis of the evidence base in this crucial area of study.