Health Research Methodology, 2nd edition by WHO is a comprehensive guide for conducting research in the field of health. This book focuses on providing a step-by-step approach to designing, implementing, and analyzing health research studies. It covers various research methods and tools used in the field, including quantitative and qualitative research techniques, data collection methods, study design, sampling techniques, and data analysis. The book also emphasizes ethical considerations in health research and provides guidelines for research integrity and protection of human subjects. With its clear explanations, practical examples, and useful tips, this book is a valuable resource for students, researchers, and professionals in the field of health research.