Drug discovery is the process of identifying novel therapeutic entities, with the combination of clinical, computational, translational and experimental models. This is done through the inventive process of drug design, which discovers novel medications on the basis of information about a biological target. Drug design process involves designing of molecules, which are complementary in charge and shape of the molecular target with which they will bind and interact. This process of designing drugs utilizes bioinformatics approaches and techniques of computer modeling but is not totally dependent on them. In spite of various advances in the field of biotechnology and in the understanding of biological systems, the process of drug discovery is difficult, costly and lengthy. There is a high rate of attrition in the discovery of new therapeutics. This book contains some path-breaking studies on drug discovery and design. Also included herein is a detailed explanation of the methods, challenges and applications of drug discovery and design. A number of latest researches have been included to keep the readers up-to-date with the global concepts in this area of study.