A pharmaceutical drug or a medication is used to diagnose, cure, treat or prevent a disease. Drug therapy depends on the science of pharmacology for research and on pharmacy for proper management. Drug development is the process of identifying a therapeautically useful compound through drug discovery, with the help of which a new drug is brought to the market. It is undertaken by pharmaceutical companies, academic scientists, and governments. Drug discovery and development includes pre-clinical research, clinical trials and obtaining regulatory approval to market the drug. This book contains the different approaches, evaluations, methodologies and advanced studies in the field of drug discovery and development. It is a compilation of chapters that discuss the most vital concepts and emerging trends in the field. This book is a vital tool for all researchers and students in this field.