Preface -- The skin lipidome under environmental stress – Technological platforms, molecular pathways and translational opportunities -- Squalene and skin barrier function: From molecular target to biomarker of environmental exposure -- Sunlight-induced DNA damage: molecular mechanisms and photoprotection strategies -- Urocanic Acid and Skin Photodamage: New Light on an Old Chromophore -- The Skin Extracellular Matrix as a Target of Environmental Exposure: Molecular Mechanisms, Prevention and Repair -- Nitric Oxide Derivatives and Skin Environmental Exposure to light: From Molecular Pathways to Therapeutic Opportunities -- Melanocortin 1 receptor (MC1R) as a global regulator of cutaneous UV responses: molecular interactions and opportunities for melanoma prevention -- The Cutaneous Melanocyte as a Target of Environmental Stressors: Molecular Mechanisms and Opportunities -- The Role of Epidermal p38 Signaling in Solar UV Radiation-induced Inflammation: Molecular Pathways and Preventive Opportunities -- UV-Induced Chemokines as Emerging Targets for Skin Cancer Photochemoprevention -- TLR3 and Inflammatory Skin Diseases: From Environmental Factors to Molecular Opportunities -- Sirtuins and stress response in skin cancer, aging, and barrier function -- Cutaneous Opioid Receptors and Stress Responses: Molecular Interactions and Opportunities for Therapeutic Intervention -- Regulation of Cutaneous Stress Response Pathways by the Circadian Clock: From Molecular Pathways to Therapeutic Opportunities -- Endocannabinoids and Skin Barrier Function: Molecular Pathways and Therapeutic Opportunities -- The aryl hydrocarbon receptor (AhR) as an environmental stress sensor and regulator of skin barrier function: Molecular mechanisms and therapeutic opportunities -- Biological cell protection by natural compounds, a second line of defense against solar radiation -- The Cutaneous Microbiota as a Determinant of Skin Barrier Function: Molecular Interactions and Therapeutic Opportunities -- Sensing Environmental Factors: The Emerging Role of Receptors in Epidermal Homeostasis and Whole-Body Health -- The Cutaneous Circadian Clock as a Determinant of Environmental Vulnerability: Molecular Pathways and Chrono-pharmacological Opportunities -- Psychological stress as a determinant of skin barrier function: Immunological pathways and therapeutic opportunities -- Index.