The World Health Organization (WHO) has long recognized the importance of health in development, emphasizing that a healthy population is essential for sustainable development. Under the leadership of Dr. Horwitz, the WHO established the Office of the Director-General (OPAS) as a technical institution focused on planning and policy-making, moving away from political decisions. The OPAS has since evolved into a key player in global health, promoting health as a universal right and respecting cultural diversity. It has faced new challenges, such as emerging diseases, and continues to develop strategies for effective and equitable health care. The book "Adherence to Long-Term Therapies: Evidence for Action" is part of a global initiative by the WHO, aimed at improving adherence to long-term therapies for chronic diseases. It is directed at health policymakers and managers, seeking to enhance adherence rates to improve patient health and increase the efficiency of health systems. The book outlines five dimensions of adherence: social and economic factors, health systems and healthcare professionals, therapy-related factors, health condition-related factors, and patient-related factors. The book is divided into three sections, with 15 chapters, five appendices, and an extensive bibliography. It discusses the magnitude of the adherence problem, its impact on health systems, and strategies to improve adherence. It also provides specific recommendations for health systems, emphasizing the need for a multidisciplinary approach. The book covers specific diseases, discussing adherence challenges and interventions. Appendices provide theoretical models, declarations for managers, and tables summarizing factors and interventions related to specific conditions. The book is a crucial reference for health professionals and policymakers, offering valuable insights into improving health outcomes through better adherence to long-term therapies.The World Health Organization (WHO) has long recognized the importance of health in development, emphasizing that a healthy population is essential for sustainable development. Under the leadership of Dr. Horwitz, the WHO established the Office of the Director-General (OPAS) as a technical institution focused on planning and policy-making, moving away from political decisions. The OPAS has since evolved into a key player in global health, promoting health as a universal right and respecting cultural diversity. It has faced new challenges, such as emerging diseases, and continues to develop strategies for effective and equitable health care. The book "Adherence to Long-Term Therapies: Evidence for Action" is part of a global initiative by the WHO, aimed at improving adherence to long-term therapies for chronic diseases. It is directed at health policymakers and managers, seeking to enhance adherence rates to improve patient health and increase the efficiency of health systems. The book outlines five dimensions of adherence: social and economic factors, health systems and healthcare professionals, therapy-related factors, health condition-related factors, and patient-related factors. The book is divided into three sections, with 15 chapters, five appendices, and an extensive bibliography. It discusses the magnitude of the adherence problem, its impact on health systems, and strategies to improve adherence. It also provides specific recommendations for health systems, emphasizing the need for a multidisciplinary approach. The book covers specific diseases, discussing adherence challenges and interventions. Appendices provide theoretical models, declarations for managers, and tables summarizing factors and interventions related to specific conditions. The book is a crucial reference for health professionals and policymakers, offering valuable insights into improving health outcomes through better adherence to long-term therapies.