This book is a fruit of a collaborative work from several international scientists. It will be a useful resource for researchers, students, and clinicians. Each individual chapter could serve as a prescribed reading for postgraduate students and clinicians specializing in and practicing clinical pharmacology and toxicology, pharmacotherapy and pharmacotherapeutics, pharmacovigilance, and toxicovigilance, as well as those involved in clinical research, drug discovery, and development. Every chapter in this book discusses and provides illustrations on the theme discussed based on authors' understanding and experience while summarizing existing knowledge. In doing so, each chapter provides a new insight that would benefit a novice as well as a seasoned reader in understanding the pharmacokinetic mechanisms and risk factors involved in the occurrence of adverse effects of drugs.