Developing a new drug requires a great amount of research work in chemistry, manufacturing, preclinical science, and clinical trials. Drug reviewers in regulatory agencies around the world bear the responsibility of evaluating whether the research data support the safety, effectiveness, and quality control of a new drug product to serve public health. Every country has its own regulatory authority, which is responsible to enforce the rules & regulations and issuing guidelines to regulate the marketing of the drugs. This book focuses on the New Drug Application (NDA) approval process in different countries like the USA, Europe, and India.