This book highlights the significance of medicinal chemistry in the context of drug discovery and development (DDD), emphasizing its multidisciplinary nature, which involves collaboration among biologists, toxicologists, pharmacologists, medicinal chemists, microbiologists, and bio-pharmacists. It underscores the authors' experience, with over 30 years of teaching and interaction with graduate students across various universities. This book is intended to serve as a handy but comprehensive textbook for the undergraduate students preparing for medicinal chemistry III. The book is written in an easy and straightforward style according to the revised syllabus of Pharmacy Council of India. This volume focuses on twelve chapters covering essential topics like antibiotics, prodrugs, antimalarials, antitubercular agents, and several others related to antiinfective agents and drug design. Each chapter offers an introduction, classification, structure“activity relationship (SAR) and detailed gives information on individual drugs, making it easier for the students to understand the topics clearly. K Ilango MPharm, PhD, FIC is currently Professor and Principal, Tagore College of Pharmacy, Chennai. P Valentina MPharm, PhD is currently Professor and Principal, PERI College of Pharmacy, Chennai.