This book describes the theories behind the field of pharmacokinetics and its application, with a focus on mathematical modeling. Designed as an advanced-level textbook for graduate courses, the book provides a complete and practical coverage for those who need to understand pharmacokinetics theory and applications. Both students and practicing professionals can gain from the approach, which is a comprehensive one that goes beyond the basics to the applied practices of math models. Among the topics covered are metabolite pharmacokinetics, in vitro / in vivo correlation, and Caco cells alongside the up-to-date presentation of physiological models. Each chapter ends with discussion problems and there is a companion website for readers to access more problem sets with questions and answers.