The book was written about Drug discovery and Quantitative Structural Activity. Quantitative structure-activity relationships (QSAR) have been applied for decades in developing relationships between physicochemical properties of chemical substances and their biological activities to obtain a robust statistical model for predicting the activities of new chemical entities or molecules.QSAR attempts to correlate structural, chemical, statistical, and physical properties with biological potency using various mathematical methods.Drug discovery is the process of identifying and characterizing molecules with the potential to safely modulate disease, aiming to bring medicines that can improve patients' lives. Target Identification And Validation.Hit Discovery Process.Assay Development And Screening.High Throughput Screening.Hit to Lead.Lead Optimization.Active Pharmaceutical IngredientThe discovery of a new drug molecule is required for treating a disease or illness for which no other treatment exists or it provides additional advantages over the prevailing treatments such as lesser adverse effects, higher therapeutic efficacy, improved amenability, and fewer drug-drug interactions, etc.