Textbook of Public Health has been compiled in collaboration with more than 150 professors of medical sciences universities in Iran. This three-volume series consists of 14 chapters and its content has been compiled in accordance with the latest revisions of various disciplines in medical sciences universities, Islamic Azad University, Payam-e-Noor University and the content of public health curricula of prestigious universities around the world. This book addresses various aspects of health, including physical, mental, social and spiritual health. The fourth edition of the book has revisited many of the previous topics and added new ones to previous topics, including chapters on "Environmental Toxicology", “Social Epidemiology”, “Adolescent and Youth Development”, “Public Health” and many others.