Public health is considered as the cornerstone and basis of health, commonly and in medicine. It is described as the science and art of prolonging life, preventing disease and promoting health through the systematized efforts and smart choices of organizations, private and public, society, communities and individuals. This field has evolved by the incorporation of multiple factors, knowledge fields, professionals and it has also been promoted by various technologies, primarily - information technology. As a transforming field of knowledge, public health needs information based on evidence and timely updates. This book provides up-to-date information on several topics associated with actual fields of interest in this emerging and exciting medical science, with the philosophy and conception to enhance the health of the population. Rather than treating illnesses of specific patients, taking decisions regarding cumulative health care that are based on the best available, recent, authentic and significant evidence, are finally within the context of available resources. This book offers a broad geographical perspective since information in this book has been contributed by researchers and scientists from across the globe. It has been organized into four major sections: Methods in Public Health; Healthcare Systems; Evidence-based Public Health and Communicable Diseases. All these aspects make this book a great update on several subjects of world public health.