It is essential to build effective health systems to deliver universal health coverage, especially for low-middle income countries. This action guide presents key practical actions within primary health care that contribute to promote public and community health, prevent disease, improve living conditions, water, sanitation, nutrition, immunization, and encourage the adoption of healthy lifestyles. Written with a particular focus on low-middle income countries, it explains key approaches and provides practical methods to developing effective health services and preventive programmes, including for hospitals, health centres, and community services, and particularly for mother, neonatal, and child health. It also explores the operational, gender, social, and economic influences on health and how to choose the best intervention strategies. This third edition has been thoroughly updated on communicable and non-communicable diseases, including new and revised chapters on health systems