Medicinal Chemistry is a discipline that serves as the chemical basis for understanding the biological effects of drugs. It attempts to integrate concepts in organic chemistry, biochemistry, pharmacology, physiology and molecular biology and apply them to the understanding of drug action. It is one of the most rapidly developing areas within the discipline of Chemistry, both globally and locally. It is the study of the design, biochemical effects, regulatory and ethical aspects of drugs for the treatment of disease. Medicinal chemistry is the application of chemical research techniques to the synthesis of pharmaceuticals. This book is primarily intended for the students and professionals in the pharmaceutical industry. Assuming little prior knowledge of the subject, the book gives a concise introduction to the chemistry of therapeutically active compounds. It also includes a brief discussion on drug development from the discovery to research stage leading to final product.