Pharmaceutical drugs refer to the chemical substances used to prevent, diagnose, cure or treat diseases. The duration of their usage varies according to the disease. They are classified on the basis of drug classes, namely, drugs having similar chemical structures, related mode of action, similar mechanism of action, and drugs which are used in treating similar diseases. The process through which new medications are discovered is called drug discovery. The process involving the introduction of a new drug to the market after its discovery is called drug development. The topics included in this book on the discovery and development of pharmaceutical drugs are of utmost significance and bound to provide incredible insights to readers. It explores all the important aspects of this field in the present day scenario. This book will prove to be immensely beneficial to students and researchers in these fields.